Doom Roguelike Equipment Analysis: Mod Packs

Mod Packs are one of the more original aspects to Doom Roguelike's design -'original' in the sense of 'not really based on official Doom games', to be clear. Systems like Mod Packs have shown up in plenty of games years before Doom Roguelike existed, after all.

Anyway, Mod Packs can be applied to weapons, Armors, and Boots, to modify their parameters in manners dependent on what Mod Pack you're using as well as what you're applying it to. You specifically apply a Mod Pack to stuff you have currently equipped: upon using a Mod Pack, you normally get a prompt asking you whether you want to apply it to (w)eapon, (a)rmor, or (b)oots, where the parenthetical letter tells you which key input is for which piece of gear, and '(w)eapon' will specifically apply the Mod Pack to the weapon in your Weapon slot. (By which I mean you cannot apply Mod Packs to the Prepared slot, even though weapons go into it) This can be a nuisance when you want to apply Mod Packs to a piece of gear you're not interested in using right now, but is mostly sensible enough.

By default, you can apply a single Mod Pack to a given piece of gear. If you attempt to apply a second Mod Pack, you'll get a catchall error message about how you can't modify that piece of gear further with that Mod Pack... unless the pair of Mod Packs would produce a Basic Assembly, but that's for next post. Ranks in Whizkid increase how many Mod Packs you can apply to gear: this is oddly complicated to get into.

First of all, the increase has two models to it: if you're looking at a ranged weapon, Whizkid adds 2 'slots' per rank to the ranged weapon. If you're looking at Armor, Boot, or melee weapons, you only add 1 'slot' per rank.

Second, there's the consideration of individual Mod Pack caps, which once again operates under two models: ranged weapons will accept up to 3 copies of a given Mod Pack type. Armor, Boots, and melee weapons will not accept duplicates.

Third, I have to touch a little bit on Assemblies here, for a couple reasons. The first reason is that Assemblies can require 'illegal' Mod Pack counts -this is pretty common outside of ranged weapons, in fact, where a lot of Assemblies require two copies of a Mod Pack even though the gear will only accept one copy. The second reason is that if you have Whizkid 2, you can apply a single Mod Pack to an Assembly (As of 0.9.9.8, Technicians can get Whizkid 3 and apply two Mod Packs to Assemblies), and contrary to what you might intuitively expect, an Assembly is a 'clean slate': Fireproof Armor, for example, is made from a Technical Mod and a Bulk Mod, but you are free to apply a Technical Mod and/or Bulk Mod to a Fireproof Armor.

Also, I've already been over this pretty heavily, but Uniques can't accept Mod Packs at all by default, except the Technician can apply Mod Packs in varying extents to many Uniques as of 0.9.9.8 (They could do this to two weapons and one Armor in 0.9.9.7, but it didn't come up often), and the Combat Translocator can't be modded at all either even though it's classed as an Exotic. I should also explicitly say that only weapons, Armor, and Boots can be modded: you can't mod the special ammo items that can go in the Prepared slot, nor mod permanent gear that sits in inventory like the Hell Staff.

Anyway, it's worth pointing out that the 'weight' of Mod Packs is set up so common Mod Packs -Power, Bulk, Technical, and Agility- are collectively thirty times as likely to spawn in as Exotic Mod Packs are. (You can say the same for each individual comparison, too, that eg Bulk Mod Packs show up thirty times as often as Onyx Mod Packs) Thus, common Mod Packs are 'cheap'; Assemblies that don't use Exotic Mod Packs are much easier to assemble, even if they use more Mod Packs, than Assemblies that use any Exotic Mod Packs.

It is in fact pretty normal for a standard run to simply never have any Exotic Mod Packs spawn through standard generation at all, where a standard run generally finds 3+ copies of each common Mod Pack type.

But on to specifics.

Power

Ranged weapon: Adds another side to all damage dice, or another damage die, whichever is the larger number on that weapon. In a tie, sides are picked for the increase.

Melee weapon: Adds another side to all damage dice.

Armor: Increases Protection value by 2 points.

Boots: Doubles Protection value.

Used in: Chainsword, Piercing Blade, Elephant Gun, Nanofiber Armor, High Power Weapon, Power Armor, Tactical Shotgun, Tower Shield, Plasmatic Shrapnel, Double Chainsaw, Energy Pistol, Burst Cannon, VBFG 9000, Nanofiber Skin Armor, Nano-shrapnel, Focused Double Shotgun, Demolition Ammo, Cybernano Armor, Ripper, Cerberus Armor, Cerberus Boots, Mother-In-Law.

Minimum Floor: 7

The simple summary of what Power Mod Packs do to ranged weapons is that they improve their damage in a least-impactful, low-gameability way: if they consistently added a die, you'd be encouraged to use them on weapons with large dice, where if they always increased dice sides you'd be encouraged to prioritize using them on weapons with many dice, which either way would be a weird, dumb bit of design. It's nice when Doom Roguelike makes efforts to avoid that kind of jank. Even if it is a little frustrating that the tiebreaker behavior is go with the improvement that doesn't give a consistent payoff.

Melee weapons unfortunately don't entirely dodge this jank, as I covered with Mjollnir's Hammer earlier, but it's pretty obvious that's a side effect of trying to have every basic Mod pack type work on all relevant types of gear.

Anyway, Power Mod Packs are crucial to many excellent Assemblies and their innate effects are all quite nice in their own right; you can never have too many Power packs.

Okay, not literally, but my point is they're good. They're so good I pretty directly rate a run's Mod Pack luck primarily off of how many Power Mod Packs it got: a run that acquires a lot of Mod Packs, but only one or two of them is Power, will often be worse off than a run that acquires fewer Mod Packs overall but gets 5+ Power Mod Packs in particular. It's a little unfortunate, honestly, given the game itself treats them as equal in value to other basic Mod Packs.

With 0.9.9.8, Technical Mod Packs became more worthwhile in a way that ablates this particular point some, but I'll get into that when actually covering Technical Mod Packs.

Bulk

Ranged weapon: Weapons with 1-2 ammo reload 25% faster. Weapons with more than 2 ammo increase ammo by 30%.

Melee weapon: Gain an additional damage die.

Armor: Adds +100 to current and maximum durability, but -10% movement speed.

Boots: Adds +100 to current and maximum durability, but -10% movement speed.

Used in: Chainsword, Gatling Gun, Nanofiber Armor, High Power Weapon, Fireproof Armor, Fireproof Boots, Double Chainsaw, Tactical Rocket Launcher, Storm Bolter Pistol, Burst Cannon, Environmental Boots, Fireshield, Nanomanufacture Ammo, Biggest FG, Cybernano Armor, Ripper.

Minimum Floor: 6

Note that Bulk mod stacking on multi-ammo weapons is more efficient than you might expect, because each mod adds 30% more based off the current ammo count. So eg a Minigun's 200 will gain 60, and then the 260 will gain 78. It's not a huge difference, since you can only stack up to three mods of a given type onto a given ranged weapon anyway, but it's still something to keep in mind if you can't or won't make an Assembly out of a weapon you're using.

Conversely, note that when a Bulk mod is improving reload speed, we hit one of the weird Mod Pack-specific rules about time: each Bulk mod you apply is considered to be a 'separate source', and furthermore the result of each step of application is rounded to the nearest 0.1s. (If it ends in a 5, it rounds to the nearest even number: 0.75 rounds to 0.8, for example, whereas 0.65 rounds to 0.6) So for example let's say you slap three Bulk mods into a basic Shotgun; if Bulk mods worked like the Reloader Trait, you'd subtract 25% three times and end up at an incredible 0.25 second reload time. With how they actually work, you instead subtract 25%, find yourself at 0.75, round it to 0.8, then subtract 25% of that, arriving at 0.6, then finally subtract 25% of that, find yourself at 0.45, and round it down to 0.4 -still much faster than your starting reload speed, but not four times faster.

The Double Shotgun's 2 second reload goes 1.5, then hits 1.125 and rounds it to 1.1, then hits 0.825 and rounds it down to 0.8. Note that this is the same final proportion as a basic Shotgun (40% of original time), but a slightly higher impact from that first Bulk mod.

The Super Shotgun and basic Rocket Launcher's 1.5 second reload of course just starts from the first step of the above. So it drops to 1.1 from the first Bulk, then 0.8 from the second Bulk, then the third Bulk brings it to 0.6. This is actually still 40% of where you started; the math here is really robust!

The Napalm Launcher's 1.2 second reload goes to 0.9, then hits 0.675 and rounds it to 0.7, then hits 0.525 and rounds it to 0.5 seconds. That's 41.76% of your starting time; the Napalm Launcher thus benefits very slightly less than usual from adding anything past 1 Bulk.

Only these 5 weapons qualify for Bulk's reload speed improvement; everything else is a melee weapon or has at least 3 ammo in its clip. Or is the Revenant's Launcher, which would qualify in terms of clip size, but is a Unique and so can't be modded -except by a Technician starting from 0.9.9.8.

It starts from 1.4 seconds of reload, so the first Bulk hits 1.05 and rounds that down to 1 second, at which point we go to 0.8 and then 0.6 seconds as I covered earlier; this is about 43% of your starting time.

Durability-wise, remember: unlike your own HP, Armor and Boot HP being displayed as a percentage doesn't actually mean anything. '100%' on them means 100 points, and the 'rot' effects of losing Armor-the-stat and losing resistances when dropping below 50% and again when dropping below 25% is not, in fact, out of the percentage of durability they provide. An Armor with a maximum of 200 points will not suffer penalties until its durability stat is 49 or less: as such, a Bulk Mod Pack roughly triples the damage needed for your Armor or Boots to start losing effectiveness!

Conversely, Armor Shards and Armor-repairing Levers are repairing a fixed number of points of durability, and thus fully repairing a Bulk-modded piece of gear will require more such repairs. (They both provide 25 points for Armor. Armor Shards provide only 10 points for Boots, while Levers provide 25 points) On the other hand, Megaspheres simply set durability to max, so in the late game Bulk Mod-provided durability can hold up better than you might expect.

I don't really get why Bulk Mods make movement slower when applied to Armor and Boots. This is the only time a Mod Pack has an explicit trade-off for applying, and it's such a strange thing to do given that Bulk's benefits to Armor and especially Boots are pretty clearly overlapping with and overall worse than Power's benefits -after all, taking less damage means losing less durability means it takes longer for durability loss to cripple the defenses of an Armor or Boots. So why is Bulk saddled with an explicit disadvantage?

I should also emphasize that if you have or intend to get Reloader 3, a Bulk Mod lowering reload time is usually providing little or no benefit since Reloader 3 brings 1 second of reload time down to the minimum duration of 0.1 second. Also, most of the weapons Bulk Mods lower reload time on are Shotguns or Rocket Launchers, which of course can be reloaded by Shottyman instead, which cares about movement speed rather than reload time, so it's often dubious to spend a Bulk Mod on reducing reload time for that reason.

For these and other reasons, I generally consider Bulk Mod Packs the lowest-value of common Mod Packs. They have uses for certain notable Assemblies (Fireproof Armor and Nanomanufacture Ammo being the most noteworthy overall), but a lot of runs will struggle to significantly leverage more than a handful of Bulk Mod Packs. Melee runs are a partial exception since their behavior is favorable for melee weapons, but this is hampered by melee weapons not accepting duplicates: you can't slap three Bulk Mods onto a melee weapon. And since melee weapons don't have any mechanics to encourage having swaps, it's not like you'll drop Bulk Mods on multiple melee weapons. (Exception: a Malicious Blades run wants to assemble two Chainswords and then put Bulk Mods on them, which is a total of 4 Bulk Mods needed)

I kind of wish Bulk Mods did something else for melee weapons, or perhaps didn't work on them at all. I get how we arrived at this situation -Bulk Mods benefit ammo/reloading, when melee weapons don't have ammo at all, and fire speed and Accuracy are covered by the next two Mod Packs- but it's an odd/janky bit of special-casing, and Exotic Mods show the game is able and willing to have cases where a Mod Pack simply doesn't benefit everything moddable. Given you can't stack multiple copies of a Mod Pack on melee weapons, Bulk could in fact have done something more 'on/off switch'-esque, rather than needing to do behavior that stacks sensibly. Or it could've done something that can technically scale but been kept design-safe by the lack of stacking: adding an Energy-draining effect to the weapon, for example.

Technical

Weapon: Attacking time reduced by 15%.

Armor: Increases Bullet, Shrapnel, and Melee resistance by 20%, and increases Fire, Plasma, and Acid resistance by 10%.

Boots: Increases Bullet, Shrapnel, and Melee resistance by 20%, and increases Fire, Plasma, and Acid resistance by 10%.

Used in: Speedloader Pistol, Micro Launcher, Tactical Shotgun, Fireproof Armor, Fireproof Boots, Ballistic Armor, Grappling Boots, Lava Boots, Storm Bolter Pistol, Energy Pistol, Environmental Boots, Fireshield, Hyperblaster, Focused Double Shotgun, Demolition Ammo, Cybernano Armor, Ripper, Cerberus Armor, Cerberus Boots.

Minimum Floor: 5

Technical's effect on weapons is another Mod Pack special-casing, and works the same as with Bulk's effect on reload speed: each Technical mod is a separate source, their individual results are rounded, 0.5 results round to the nearest even.

Thus, on a weapon with a firing time of 1 second, your first Technical mod actually shaves it down to 0.8 seconds (Hit 0.85, round to nearest even), your second hits 0.68 and rounds it to 0.7, and your third hits 0.595 and rounds it to 0.6.

Most weapons have a firing time of 1 second, so this is the most common result. Somewhat less common is 1.5 seconds or 0.8 seconds base firing duration.

1.5 seconds is 1.3 (1.275, round up), 1.1 (1.105, round down), and then 0.9. (0.935, round down) This would produce 0.825 if they stacked additively.

0.8 seconds is 0.7 (0.68, round up), 0.6 (0.595, round up), and then 0.5. (0.51, round down) This would produce 0.44 if they stacked additively.

The Minigun uniquely has 1.2 seconds as its base fire time. So three Technical Mod Packs goes 1 second (1.02, round down), 0.8 seconds (Hit 0.85, round to nearest even), then last you hit 0.68 and round it to 0.7.

The Blaster uniquely has 0.9 seconds as its base. So three Technical Mod Packs goes 0.8 seconds (0.765, round up), 0.7 (0.68, round up), and then 0.6. (0.595, round up)

The Trigun has 0.7 seconds. It can only be modded once, only by a Technician, so at best you can get to 0.6 seconds. (But why are you doing that when Son of a Gun 5 hits the cap on time anyway?)

Note that since this all modifies the weapon's base fire time, it modifies what Finesse is running off of.

Also, prior to 0.9.9.8, Technical Mod Packs had a different effect on Armor and Boots: they added 25% knockback resistance. I quite appreciate this change for Armor -the knockback resistance was difficult to care about, where the damage resistance is clearer in what the value is- but Boots would've been better off retaining the knockback resistance: only the Fire and Acid resistance matter at all to Boots, and the low resistance amount means a Technical Mod Pack being added to Boots is unreliable about actually doing anything.

Also, in 0.9.9.8 Armor and Boots Assemblies have a bug with Technical Mod Packs: any resistances the Assembly inherits from the base item will in fact inherit the Technical Mod Pack resistance modification if a Technical Mod Pack was applied at an earlier step than the completion of the Assembly. ie if you Assemble a Fireproof Armor (Bulk+Technical), applying the Bulk first will mean the resulting Armor won't have the +20% physical and +10% energy resistances. I actually think the inheritance should be the default behavior, but it's certainly wonky that some Assemblies can be superior/inferior based on what order you applied the Mod Packs in.

On the topic of Assemblies, I should point out that Technical Mod Packs are unique among the basic Mod Packs for the fact that an Assembly never requires more than 2 of them. The other basic Mod Packs all have at least one Assembly that requires 3 copies of that Mod Pack type: as such, Technical Mod Packs are uniquely low in demand in the sense that you'll never be denied an Assembly by the game only generating 2 copies of them.

Anyway, the fact that Technical now adds resistances is another thing overlapping with Bulk's benefits, for the same reason as Power: reducing damage taken reduces how much durability you lose when attacked. So that pushes 'Bulk on Armor' even further back as a priority.

The resistances themselves are less good than a Power Mod Pack from an early-game perspective, but against late-game enemies a Technical Mod Pack tends to provide similar or greater damage reduction than a Power Mod Pack, even when talking the energy damage types Technical provides less of. An Archvile's 20 Fire damage, for example, loses 2 damage from 10% more Fire resistance, and Revenants and Mancubi can hit even harder and so lose more. Plasma damage threats are especially consistent about favoring Technical over Power since Plasma ignores half the victim's Protection and resistances round up: 10 and less damage still results in 10% resistance shaving off 1 point of damage, after all, when Power's 2 Protection only reduces damage from Plasma by 1 point as well.

As such, in 0.9.9.8 it tends to be better to default to Technical over Power for Armor unless you're early in the run.

This is not so for Boots, to be clear, since Boots only have to worry about fluid-based damage and that simply never gets high enough to favor Technical's resistance package. Though the distinction is irrelevant for Steel Boots with their 1 Protection, since for some reason Power Mods specifically double Protection on Boots rather than adding +2.

Agility

Weapon: +1 accuracy.

Armor: +15% to movement speed.

Boots: +10% to movement speed.

Used in: Piercing Blade, Speedloader Pistol, Tactical Armor, Tactical Boots, Ballistic Armor, Assault Rifle, Antigrav Boots, Hyperblaster, Focused Double Shotgun, Cerberus Armor, Cerberus Boots.

Minimum Floor: 6

Agility is our final Weird Mod Pack Rule for time modification, in that the game simply rolls Agility's effects directly into the Armor or Boots movement speed modifier and treats that number as one source; thus, an Agility mod applied to Green Armor takes its base -10%, adds Agility's +15%, and arrives at your Green Armor now providing +5% movement speed. Do note that Armor and Boots are separate sources from each other; this can be advantageous, as it means if your Boots and Armor are both boosting your movement speed you get a bigger boost. (+15% and +10% would not become 125%, but rather 126.5%) Though conversely it makes positive modifiers on one less effective at canceling negative modifiers on the other; -25% from Armor alongside +10% from your Boots results in 82.5% final speed, not 85% like it would if they just got added together. On the third hand, it makes stacking penalties a little less crushing; if your Armor and Boots are both -25%, this results in 56.25% final speed instead of 50%. (Though that doesn't matter to Agility application)

It's almost never worth putting an Agility Mod Pack on a weapon unless it's needed for an Assembly. Putting an Agility on an Armor is equivalent to the movement provided by a rank of Hellrunner; putting an Agility on a weapon is equivalent to half a rank in Eagle Eye. (And melee weapons have this even worse, since Brute is even better than Eagle Eye for melee weapons) Better to invest in Eagle Eye and dump Agility Mod Packs onto your Armor than to invest in Hellrunner and dump Agility Mod Packs onto your weapon, among other implications. Not even touching on the fact that Shotguns get literally zero benefit!

One exception is Ammo Chain Marines. Ammo Chain bars access to Eagle Eye, and if you don't luck into a Laser Rifle your weapons are all low on Accuracy, enough so that some extra Accuracy heavily boosts your expected damage output: a Chaingun expects to hit 50% of the time at the edge of your line of sight. Slap a couple Agility Mod Packs on it, and suddenly you're hitting 74% of the time instead, a nearly 50% increase in damage output. That's better returns than putting a Power Mod Pack on gives, and indeed is better than the returns on using a Technical or Firestorm Mod Pack.

Unsurprisingly, Agility mods being applied to weapons is particularly worthless on Max Carnage runs, since you're already expecting to have max hit chance in almost all conditions.

Unfortunately, in conjunction with Agility being basically a freebie boost on Boots, Agility is pretty heavily stacked toward 'Assemble Tactical Boots, then at Whizkid 2 put Agility on them, then largely stop caring about Agility if you don't have key Assemblies relevant to your build'. It's at least needed for Cerberus Boots and Cerberus Armor and so retains relevancy in Angel of 100/Archangel of 666 runs, but it's dubious to use Agility for 'supermodding' weapons (And with 0.9.9.8 granting Eagle Eye access to Bullet Dance, it really is mostly restricted to Ammo Chain Marines for notable utility), and it's not like it makes sense as your 'capstone' mod for weapon Assemblies.

This is in part commentary on one of the weakest aspects of Doom Roguelike's design: the Accuracy system doesn't have much 'give' to it. I actually like the design of the game's Accuracy system overall! But it's not really designed to give Accuracy modification much 'running room', which hampers Agility Mod Pack design, Eagle Eye's design, and to a lesser extent basically everything else that interacts with Accuracy modification. (Like Running) I wasn't really surprised when Jupiter Hell ripped out this system and replaced it with a different model.

Anyway, on to Exotic Mod Packs!

Firestorm

Weapon: Adds 2 tiles of radius if weapon has at least three tiles of blast radius. Adds 2 shots per burst to weapons that fire at least 3 shots per burst. For weapons that meet both conditions, provides the +2 shots benefit. (Exception: the Tristar Blaster instead gains 2 tiles of radius) Has no effect on weapons that fit neither category, but can still be applied to such weapons.

Armor: N/A

Boots: N/A

Used in: Demolition Ammo, Biggest FG, Mother-In-Law.

Minimum Floor: 10

Notice that Shotguns and most Pistols get zero benefit from Firestorm packs. Shotguns don't even have a potential Assembly to get use out of the Firestorm Mod Pack. And yes, the game is perfectly happy to let you apply a Firestorm pack even when it's useless. Also note that all three Assemblies require Whizkid 2 -if the innate benefits of Firestorm are useless to you and you don't intend to take Whizkid, Firestorm Mod Packs are worthless.

The first of two Exotic Mod Packs that can only be applied to weapons. Being exclusive to weapons, the game skips the usual Mod Pack prompt of asking you where you want to apply it, which has the unfortunate effect of making it particularly easy to make an input error and whoops you've botched a planned Assembly!

What makes such an event particularly frustrating is that both of these Exotic Mod Packs are quite lackluster.

In the Firestorm Mod Pack's case, there's three layers to the issue.

First of all, as I already noted it doesn't do anything for Shotguns. Shotguns are your default staple weapon, very effective even without Trait investment to support them and with key advantages like being unable to miss, so not getting to boost them inherently pushes the Firestorm into a more niche position.

Second, the explosive radius increase is much less appealing than a player going into the game 'blind' might assume. Explosions in Doom Roguelike suffer damage drop-off every 2 tiles out from the center of the explosion, so the damage gain from firing into a group with a Firestorm-boosted Rocket Launcher or the like is much less than you might hope; the added radius simply adds less damage, with this getting more true as the radius grows.

Third and most egregious, firing additional shots from a rapid-fire weapon necessarily means spending more ammo, even if it's overkill, and isn't even that significant a boost in damage on any relevant weapons. If you're an Ammo Chain Marine in specific a Firestorm Mod Pack applied to a Chaingun or similar is without real disadvantage, but outside that specific situation it's arguably an active disadvantage to be spraying more bullets. Ammo management is perpetually a concern if you haven't either gotten Ammo Chain or performed one of the ammo-solving Assemblies, after all. (I suppose a Firestorm pack applied to a Nanomanufacture weapon is decent enough... if you happen to get the multiple Exotic Mod Packs necessary for this to occur)

The fourth and final issue is the small Assembly list available to Firestorm Mod Packs. Two of its Assemblies are Master Assemblies that require you have two Exotic Mod Packs (Which is an uncommon event in a standard run unless you're absurdly good at the game), and while they're overall very strong Assemblies the long odds of being able to Assemble them makes it difficult to justify trying to shoot for them in most runs. The third Assembly is the dubious Demolition Ammo Assembly, which only requires common Mod Packs aside a Firestorm itself but is still a Master Assembly and has benefits that are generally only good in an Angel of Marksmanship Challenge where the Assembly becomes your only option for busting holes in walls. (Such as to access The Wall/Containment Area)

This combination of dubious benefits from the base effect and a dubious Assembly list makes Firestorm probably the most consistently disappointing Mod Pack to find.

I really wish the extra shots for rapid-fire weapons didn't spend ammo, as an inherent effect of the Firestorm Mod. That would do a lot to make it appealing. It's not like this would be a gamebreaker -Nano Mod Packs are very obviously much more ridiculous.

The one qualifier to all this is that for BFGs, additional radius is not diminishing returns on added damage, making them probably the best recipients for Firestorm Mod Packs. Notably, the Biggest FG requires two Firestorm Mod Packs: if BFGs didn't do full damage across their entire radius, this would be a frustrating quality, but as-is there's a decent argument that you'd want to do almost the recipe anyway. Putting two Bulk Mod Packs and a Firestorm Mod Pack on a BFG in hopes you get another Firestorm Mod Pack to make the Biggest FG is only potentially sub-optimal if you're refusing to put a third Bulk Mod Pack and/or a Technical Mod Pack or two in because you're hoping for the Biggest FG.

It's really unfortunate both the game and the wiki don't suggest this quality of BFGs exists...

Sniper

Weapon: One Sniper pack removes Accuracy penalties for distance. Two Sniper packs removes the 50% chance that a target you don't have vision on will be missed regardless of Accuracy. Three offers no further benefits.

Armor: N/A

Boots: N/A

Used in: Plasmatic Shrapnel.

Minimum Floor: 10

Prior to 0.9.9.8, this used the same purple color as Firestorm Mod Packs, leading to many moments of false hope where you thought you'd found whichever one you wanted and sorry, it's the other one you don't care about. I'm so glad 0.9.9.8 fixed that.

Anyway, notice that just like Firestorm Mod Packs, Sniper Mod Packs have no benefit to Shotguns, unless one counts using one to make them into Plasmatic Shrapnel versions.

The sad thing is, the baseline benefits of a Sniper mod are so lackluster Shotgun-focused builds are actually a lot more likely to be happy to see a Sniper Mod Pack than other builds, as Plasmatic Shrapnel is a uniquely useful Assembly. So let's talk about the issues with Sniper's 'generic' benefits.

The first-application benefit is hampered by how limited the impact of range on Accuracy actually is: at standard line of sight, you're only suffering a -2 penalty, and thus one Sniper mod is generally at most equivalent to two Agility mods... and then you actually spend a fair amount of time shooting at somewhat closer ranges, where it's only canceling a -1 penalty, in which case an Agility mod is exactly equal to it. And if you're shooting from very close, now the Sniper mod is outright worse than an Agility pack!

Now, Accuracy penalties stack up infinitely with distance even past line of sight, but past line of sight you're just firing blindly into the dark with no idea whether you're actually pointing your weapon at any enemies, and furthermore 50% of all shots that would otherwise have hit instead miss if the victim is not visible to you. Without a Tracking Map (or the 'reveal last three enemies' effect added by 0.9.9.8), you won't even know if an enemy is on your firing path at all at the distances a Sniper pack has a big impact at, and even with a Sniper mod equipped you're still losing 50% of your shots to the darkness penalty. 

It's slightly better if you're a Cateye Scout since your edge-of-vision penalty is -3 and you necessarily have Intuition to be potentially taking shots at -4... but for one thing you can take Eagle Eye, and probably should if you're not doing an Angel of Max Carnage run. For another, the -4 penalty is still hitting the darkness penalty, making it dubious to take such shots even with a Sniper mod.

Now, a second Sniper mod will remove that darkness penalty... but for starters Exotic Mod Packs are rare. You can go several successful, very thorough runs without having any one run find two Sniper mods. Even an Angel of 100 run is unlikely to see multiple Sniper packs, and indeed it's possible to complete an Angel of 100 run without seeing any Exotic Mod Packs. (If a bit unexpected) This makes it difficult to justify planning for the possibility of finding a second one; the majority of the time, such planning will just make your run perform worse for no benefit. (Whether by using the first one even though it's less helpful than Agility mods, or by virtue of holding onto it instead, eating inventory space for no benefit that could've been used on something actually useful) Which in turn means that when you do find two Sniper mods in a single run, good play will probably have missed the opportunity to stack them!

Furthermore, you just plain can't get the darkness-ignoring effect on Assemblies. (Unless you're specifically playing a Technician as of 0.9.9.8) This limits its potential in general, and it's worth pointing out that a Cateye Scout (ie the build that looks upon Sniper mods relatively favorably) is specialized in rapid-fire weapons. Given the Assault Rifle Assembly can be applied to any non-Unique rapid-fire weapon, this isn't a specialty that's particularly biased away from Assemblies. It's not like it matters that it's an Advanced Assembly, not for this topic's purposes; you need Whizkid 1 to be able to apply two Sniper mods, so if you're considering that possibility you have access to Advanced Assemblies. Period.

Furthermore, there's still no way to fully reliably see enemies far enough out for the first Sniper effect to really impress. Tracking Maps will do the job, but they're uncommon and overall only get rarer as you delve deeper, and Technicians treating Computer Maps as Tracking Maps helps with this point less than you might hope. You'd need something like map-wide Intuition-sensing from a Mastery, or something, for two Sniper mods to reliably let you... you know... snipe.

This isn't even touching on how Angel of Max Carnage and Angel of Darkness further exaggerate the first benefit being the far less useful one...

Overall, Sniper Mod Packs are sufficiently bad/frustratingly-designed I kind of wish they were cut entirely. Making the Plasmatic Shrapnel Assembly use a Firestorm Mod Pack instead isn't exactly a big change to the game's dynamics (And it would make Firestorm better to find), and no other Sniper-using Assemblies exist so it wouldn't be missed: removing Sniper packs and implementing their behavior as Eagle Eye 4 and 5 would make for a smoother and more interesting experience.

Collectively, Firestorm and Sniper Mod Packs are frustrating predominately for the fact that they get lumped in with Onyx and Nano Mod Packs in terms of accessibility and commonality: they really should be their own tier of Mod Pack above the common ones but not treated as peers to Onyx and Nano Mod Packs. The game actually does this to an extent: the Scavenger Mastery can produce Sniper and Firestorm Mod Packs from disassembling Exotic gear (But not Onyx or Nano Mod Packs), and the semi-guaranteed Exotic Mod Packs from Deimos Lab/Hell's Armory give Sniper and Firestorm way more often than they give Onyx and Nano. But in terms of minimum floor and item 'weight', all four Exotic Mod Packs are treated the same.

This is wonky for two reasons. The first issue is the quality issue: Sniper and Firestorm are simply way less useful than Nano and Onyx. The game simply shouldn't be treating them as equivalently valuable.

The second issue is the difference on respective Mod Pack design: Sniper is designed so it has a unique benefit for putting two copies on one weapon. Firestorm can scale its benefits to the default maximum of 3 copies of one Mod Pack type you're allowed to load onto ranged weapons. Firestorm also has an Assembly that requires two copies of it! Onyx and Nano are both designed so putting multiple copies on a single piece of equipment makes no sense, including that there are zero Assemblies that require 2 copies of one of them. In general, you only really care about your first Onyx Mod Pack since one Onyx-modded Armor renders all other Armors unnecessary: Nano isn't quite so binary, but mostly because weapon swaps are more useful than Armor swaps and it has Assemblies for both Armor and weapons. You still care way more about your first Nano Mod Pack than any further ones, just less starkly than with Onyx.

So Sniper and Firestorm being just as rare as Onyx and Nano is also bizarre design on this level: the fact that a standard run is lucky if it gets one Onyx or Nano Mod Pack is fair both in terms of their power and in terms of the fact that copies beyond that don't add much. The fact that a run is lucky if it gets one Sniper or Firestorm is much less so, resulting in eg the benefit for stacking two Sniper Mod Packs being essentially a technicality: almost no runs have any possibility of applying two Sniper packs to one weapon, and the extreme rarity means it often makes no sense to hold onto one in hopes of getting another one and putting them both on a weapon. Same to a lesser extent with Firestorm: sure, you might get to Assemble the Biggest FG by finding a second one, but it's absurdly unlikely so are you sure you want to carry a Firestorm Mod Pack all the way from Hell's Armory/Deimos Lab to the Spider's Lair/Halls of Carnage? It's eating valuable inventory space for a slim chance of netting you that Assembly. (This is less than Sniper simply because putting a Firestorm on a BFG is nice in its own right)

Like, if Hell's Armory/Deimos Lab chose between 'one Onyx or Nano' and 'two Mod Packs from the Firestorm/Sniper pair', so you had pretty good odds of getting two copies of Sniper or Firestorm in a run, it wouldn't be nearly so frustrating to have their respective caches decide to not give Onyx or Nano, and suddenly the double-Sniper pack would be merely uncommon to be able to leverage, rather than so absurdly rare the mechanic might as well not exist. Especially if this was occurring alongside a general increase in how often Sniper and Firestorm packs generated so even having the cache give one of each would still have okay odds of one showing up through standard item generation. Another idea is that a lot of cases of Special Levels having guaranteed-but-random common Mod Packs could have a low-ish chance of being a Sniper or Firestorm Mod Pack instead. (1 in 10 chance per such common Mod Pack slot, say)

Whatever the case, the current conflation of all Exotic Mod Packs into one grouping is really wonky.

Onyx

Weapon: N/A

Armor: Durability never lowers.

Boots: Durability never lowers.

Used in: Tower Shield, Lava Boots, Fireshield, Cybernano Armor.

Minimum Floor: 10

Where Sniper and Firestorm can only be used for weapons, Onyx cannot be used for weapons. As this still means choosing between Armor and Boots, attempting to use an Onyx Mod Pack will still bring up the prompt for picking where to apply it to. The whole prompt, in fact, though if you attempt to select W for weapon the game will just cancel out of the prompt, doing nothing. It doesn't even provide an error message in that case.

While Onyx is used in only a handful of Assemblies and doesn't work on weapons at all, it's nonetheless an excellent Mod Pack. Notably, it's 100% superior to Bulk mods, as it has no penalty for being applied and durability refusing to lower is straightforwardly better than having above-max durability.

Onyx Mod Packs would in fact almost completely displace Bulk Mod Packs when it comes to Armor and Boots if it weren't for how absurdly rare Exotic Mod Packs are. Finding an Onyx Mod Pack tends to make Bulk Mod Packs even more unappealing than they already were; if you could count on Onyx Mod Packs showing up, Bulk Mod Packs would almost never make sense to apply to Armor or Boots. (Not that Bulk makes much sense to apply to Boots as-is, mind)

Onyx is in fact a bit of a 'gamebreaker', as Armor being able to break is a linchpin in the game letting Doomguy get extremely tough without becoming essentially invulnerable. Rendering your Armor indestructible renders such nigh-unkillable builds... well, actually nigh-unkillable. Melee-focused runs especially can become set for life off getting a single Onyx Mod Pack.

The one awkward thing here is that ideally you Assemble some kind of Armor (eg Cerberus Armor) and then slap the Onyx on the Assembly. So it's possible to get an Onyx Mod, but then have your Armor get shredded and die unexpectedly because you were waiting on your Finesse and then Whizkid ranks to be able to put it on an Assembly. Marines and Scouts especially may prefer to 'settle' for just slapping Onyx on a non-Assembly so as to avoid such scenarios: there's a much larger difference between 'naked' and 'not-great indestructible Armor' than between 'not-great indestructible Armor' and 'perfectly optimal Assembled Armor you then made indestructible. This is especially so in 0.9.9.8, where Technical and Power both enhance survivability when slapped on Armor!

Nano

Ranged weapon: After 5 actions pass without firing the weapon, it starts generating 1 ammo per action taken. The weapon cannot be manually reloaded or unloaded anymore.

Melee weapon: Ineligible.

Armor: After 5 actions pass without the player taking damage, starts regenerating 1% Durability per action taken.

Boots: After 5 actions pass without the player taking damage, starts regenerating 1% Durability per action taken.

Used in: Power Armor, Nanofiber Skin Armor, Antigrav Boots, Nano-shrapnel, Nanomanufacture Ammo, Cybernano Armor, Mother-In-Law.

Minimum Floor: 10

Note that Nano's effects can only kick in on currently-equipped gear: armor and boots won't self-repair if they're sitting in your inventory, and weapons won't regenerate ammo either... including that the Prepared slot doesn't count as being equipped! (Which is bizarre, given the Nuclear Plasma Rifle, Nuclear BFG, and Blaster all do generate ammo when in the Prepared slot)

Also notice that these effects occur based on actions taken, not time passing. The faster your character is, the more you can get away with stuff like ducking around a corner and waiting for your stuff to fix itself up before the enemies catch up to you!

Nano's baseline effects are okay but not the big draw of it: its Armor/Boots benefits in particular are strictly inferior to Onyx (Outside Medical Armor, I guess), but even its benefit to weapons is a tradeoff instead of a pure improvement, and it's a tradeoff only a few weapons have the right stats to not mind too much. Single-shot weapons go poorly with its behavior (Fire, wait 6 actions, fire, wait 6 actions...), while multishot weapons mostly expend multiple shots per pull of the trigger and so Nano providing 1 ammo per action is slow to fill them up. Say you put it on a Chaingun: you'll fire 10 times, then have to wait 46 actions before you can fire 10 times again. So eg an Assault Shotgun is an okay recipient, but not much else is.

However, as I noted earlier the baseline effects aren't the point: the point is Assemblies, as Nanomanufacture Ammo, Nano-Shrapnel, the Mother-In-Law, Power Armor, and Cybernano Armor all either permanently solve ammo as a problem or produce an indestructible Armor with further benefits. This is the real draw of Nano: it's amazing Assemblies.

The main reason you might consider using Nano for its baseline benefits is if you expect to not take Whizkid at all. (In 0.9.9.7, this could happen by virtue of your Mastery blocking Finesse or Whizkid) Only one of Nano's Assemblies aren't Advanced or Master Assemblies, so with no Whizkid ranks, you can't use Nano for anything but its mediocre baseline benefits and one mediocre Assembly. This is in fact part of why Whizkid access is so centralizing: solving ammo or Armor permanently is absurdly beneficial, and you can do it with Nano, but not if you don't have Whizkid!

This also means I don't have much to say about Nano itself: I'll be talking about it primarily via covering the Assemblies that use it.

Note that Nano's benefit to weapons doesn't stack. The game will let you apply multiple Nano Mods to a weapon, but it won't do anything: you might expect it to increase the amount of ammo generated per action, but nope! There's apparently code for it to reduce the number of actions before ammo or durability starts generating, but I'm mostly certain this doesn't work, and even if it does work... the difference between '5 turn delay' and '4 turn delay' is basically nothing. It will basically always be much better to try to use an extra Nano Mod Pack on another Assembly.

I should similarly point out that Nano being placed on Boots or Armor doesn't prevent them from being destroyed at 0% durability. Every Unique that has innate durability regeneration is also indestructible, so you might expect this correlation to extend to Nano, but nope. 

Surprisingly, Mod Packs have only a single graphic, internally. The graphics engine just recolors the black square inside and adds the purple aura to Exotics.

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Next time, we cover Basic Assemblies.

See you then.