Doom Roguelike Environment Analysis: Levers

Levers in Doom Roguelike have nine ten possible outcomes when pulled (0.9.9.8 added one type), rolled at floor generation. Every effect can be triggered a limited number of times for a given Lever: six of the types can be used once, while the remaining four type will roll a random number of uses on generation, ranging from 1 to 3.

Five of the single-use Levers affect the entire room they're in by default. This can sometimes 'leak' out farther than their original room if floor generation punches holes in its walls (eg via a river) and sometimes if the walls are destroyed in combat before the Lever is pulled, though I'm pretty sure this is a bug as it's inconsistent whether it happens at all and can sometimes travel pretty strangely.

The sixth single-use Lever instead always affects the entire floor. The other five single-use Levers can affect the entire floor, but you'll be forewarned via a 'level feeling' upon entering the floor so you know to be cautious of Lever-pulling... though something to be aware of is that you can get multiple Levers deciding to be map-wide, and the game sometimes will fail to give you all the appropriate level feeling messages. It's rare, but still something to keep in mind: just because you got the map-wide water flood message doesn't mean you can't also get a map-wide Lava flood Lever! (Unless of course you're confident only one Lever generated at all, such as by immediately finding a Computer Map)

Levers are also surprisingly fragile, prone to being instantly vaporized when caught in the blast of even fairly weak attacks like Imp fireballs. I'm not sure of the exact mechanics of this, as they seem to be frailer than regular items, but I can't find specifics for what the game might be doing, and the random nature of damage makes it difficult to construct a test to firmly pin down the exact numbers. It's also possible I've simply had bad luck that made Levers seem frailer than most items when they just use regular item destruction rules.

Something suggesting that they're just operating on regular item destruction rules is that, unexpectedly, Technicians use them in 0.1 seconds. This is particularly odd since Lever mechanics are more like Powerups than items, and Technicians do not use Powerups in 0.1 seconds!

Also note that Levers in Special Levels ignore most of this post's details and instead have special effects specific to the Special Level, if they have Levers at all. In all such cases pulling the Levers is necessary for '100%ing' the Special Level: they will unlock doors, spawn a boss that needs to be killed to get to important loot, etc. They're also indestructible, thankfully... aside that I've never tested what happens if fluids get into their tile and so as yet can't confirm that they're safe from such. (Thankfully, these Special Levels are designed so this is unlikely to come up: you'd basically have to be careless with either the Acid Spitter or a Napalm Launcher for it to matter)

Further note that Levers are forbidden from spawning if a floor is an Arena ("Suddenly monsters come from everywhere!"), Cave ("Twisted passages carry the smell of death..."), Maze ("Where the Hell is the way out of here!?!") or has elected to generate as a 'single-monster level'. (Which is a misleading name as several of them use mixed groups. Regardless, there are too many messages associated with these to rattle off here) These kinds of floor overall get more common the deeper you get, so Levers overall get rarer as a run progresses.

I'll be starting with the 1-3 use Levers, then covering the one always map-wide Lever, then the remaining Levers. Also note that I'm giving them names for convenience, but they mostly don't have ingame names that I'm aware. The exact details are...

Meditech Depot

Intuition 2 Description: Meditech Depot

Intuition 1 Description: Beneficial

Effect: Heals Doomguy exactly as per a Small Medpack, meaning 25% of his maximum HP plus 2 Hit Points with no possibility of overhealing. Also sets Doomguy's Tactics to Cautious. Has 1-3 charges initially. In the event that Doomguy is at or over 100%, the Lever will not heal Doomguy but also not use any of its charges, while informing the player of the nature of the Lever.

The Meditech Depot is effectively 1-3 Small Medpacks, except like Health Globes you can't cart them around in inventory: use it or lose it. Since Meditech Depots can't overheal, it's best when wrapping up a floor to get healing from Meditech Depots and then pick up Health Globes.

If you don't have Intuition, doing so on a consistent basis isn't very practical. Even with Intuition 1, there's 4 'beneficial' Lever types (3 in 0.9.9.7), one of which is useless if you hold off on it until you've killed everything on the floor, so just Intuition 1 is awkward for this. If you have Intuition 2, though, you can consistently optimize Lever usage, and so instead of pulling a Lever hoping it kills a bunch of enemies and ending up getting healed from 92% to 100%, wasting most of the Meditech Depot's benefits, you get the full value later, when you're actually below 75% HP.

This is one of many subtle benefits to Intuition ranks: IDing Levers correctly effectively gives you a 'free Medpack' intermittently, whereas a Doomguy with no Intuition ranks can't pull all the useful Levers without risking disaster, and even when things turn out well such a Doomguy still ends up using Levers non-optimally. Among other points, a Scout's raw durability being poor compared to a Marine is deceptive if you prioritize Intuition ranks in Scout runs.

Do note that Intuition ranks do not tell you how many charges a given Lever has. For Levers with variable charge counts, you'll only know how many charges remain either when the Lever disappears, or if you pull it twice and it's still around. (In which case it has one charge left)

Overall, Meditech Depots are a straightforward enough Lever once IDed one way or another: use 'em when your HP gets low enough to not waste the heal.

Armor Depot

Intuition 2 Description: Repairs armor

Intuition 1 Description: Beneficial

Effect: Repairs Doomguy's currently-equipped Armor and Boots, adding +25 durability to each. Has 1-3 charges initially. In the event that Doomguy's currently-equipped gear has no use for repairs, the Lever will not do anything but also not use any of its charges, and the player will be informed of the nature of the Lever.

Armor Depots are generally more significant than Meditech Depots because durability repair is much rarer than health restoration, durability restoration just plain cannot be carted around and stockpiled the way you can do with health restoration, and because you can cart around valuable-but-badly-damaged Armor (And Boots, though this is less important) and put it on to get it back into a usable state. (Where health has no remotely equivalent mechanic) This is especially so in the earliest portion of a run, as Armor Shards simply can't appear until the fifth floor, and Megaspheres wait until the sixteenth, making Levers the earliest source of possible Armor repair!

Armor Depots are also slightly better than an Armor Shard per use, as an Armor Shard only adds 10 durability to equipped Boots, not the 25 of an Armor Depot. I call this 'slightly' better because Boot damage is a rare thing that is more easily made a moot point than Armor damage, but it's an odd difference. (I can contrast this with the Meditech Depot behaving exactly like a Small Medpack)

In the long haul, this Lever type tends to fall off in relevance, between Megaspheres entering rotation and the potential for the player to Assemble indestructible Armor/fluid-immune Boots/regenerating Boots, but its existence is another thing giving early Intuition ranks more value than you might expect.

Monsters In A Box

Intuition 2 Description: Spawns enemies

Intuition 1 Description: Dangerous

Effect: Spawns a randomized number of enemies immediately around Doomguy. The types of enemies summoned are random as well, but based off what could legally have spawned into the floor on initial generation. These summoned enemies do not provide experience when killed, but can drop items if they carry any. Has 1-3 charges on initial generation.

For a Vampyre run, this can be a way to get your health back up without spending Medpacks. For any run that grabbed Berserker, it can also be a way to more-or-less-safely trigger Berserk before charging into a regular fight: once a melee run gets going, it's pretty normal to be killing things so quickly that often none of the spawned enemies get a turn before dying. (Especially for Blademaster Scouts, or anybody carrying the Butcher's Cleaver)

For Shotgun-focused runs, it can be worth considering pulling the Lever in hopes of Former Sergeants spawning so you can get more Shotgun ammo, especially if you're running low on ammo and have Brute ranks. This gets less and less appealing a prospect as a run goes on, as Former Sergeants get crowded out by other, much more dangerous possibilities, but still, it's something.

For other runs, there's little reason to pull such a Lever once you've IDed it. 10mm ammo and Power Cells come in at a poor rate from these Levers on average, and while an Ammochain Marine can take those odds pretty readily, they're so ammo-efficient they're pretty unlikely to meaningfully benefit from such ammo fishing.

Overall, this Lever is decent at serving as a Bad Result that discourages you from blindly pulling all Levers at all times, albeit with some odd caveats to it.

Ammo Dispenser

Intuition 2 Description: Ammo dispenser

Intuition 1 Description: Beneficial

Effect: Spawns a stack of ammo. The amount is the standard for spawning on the ground at floor generation. The type is decided by what weapon Doomguy is equipped with when he pulls the Lever, matching to the ammo used by his current weapon. (Or its base ammo type, if it's been modded to not use ammo)

I've yet to test what this does if used while carrying the Acid Spitter or most of the weapons that natively generates ammo internally, though I suspect the latter category just gives Power Cells. (Nuclear Plasma Rifles and Nuclear BFGs both do, I've tested that much)

Also, this was added by 0.9.9.8, and is a nice quality-of-life improvement in terms of improving access to the ammo you're dependent on, especially in Angel of 100/Archangel of 666 runs where ammo access is more volatile and there's basically no reason to not eventually make Levers fairly safe to gamble on. (Whether by grabbing Intuition so you're not gambling, or by getting permanent immunity to Acid and Lava so the worst results aren't a problem)

Pretty straightforward.

Kaboom!

Intuition 2 Description: Explodes Barrels

Intuition 1 Description: Neutral

Effect: Every Barrel on the floor detonates simultaneously. Only one such Lever can generate on a given floor.

I honestly don't understand why this wasn't labeled 'dangerous' for the Intuition 1 effect. In the first place, pulling a Lever within the blast radius of one or more barrels can get you hurt or killed. In the second place, even if you assume the player always moves all barrels away from any given Lever before pulling it, it can still destroy items, Powerups, and other Levers, as well as punch open walls -and destroying walls is a Lever effect that exists and does get labeled dangerous! Furthermore, Acid and Napalm Barrels can easily end up cutting off chunks of the map, making it impossible to clear the map fully or even to reach the exit without wading through hazardous terrain.

Yes, it can kill enemies for you, but on the whole just blindly detonating all the Barrels on a floor is more prone to backfiring than anything else. It's only a solid positive if you've found a Computer/Tracking Map so you can check the map composition and confirm it won't blow up anything useful or cut off important passages.

If you get the "Khe, he, he. This will be a mess..." level feeling, you should be especially wary of pulling unknown or 'neutral' Levers, especially if it's early in a run; Barrel composition is normally controlled by floor depth, where initially most Barrels will be Fuel Barrels with the occasional Acid Barrel, while late in the game literally every Barrel will be a Napalm Barrel. The level feeling that produces hordes of Barrels has a random composition completely unrelated to current depth, and so where normally it's relatively safe to pull a barrel-exploding Lever on eg floor 2, with the Barrel-generating level feeling you can easily end up forced to run through three different patches of Acid or Lava just to get to the exit.

Late in a run, especially an Angel of 100 or Archangel of 666 run, especially on higher difficulties, the Barrel level feeling can actually be pretty nice. Pulling the Lever is still probably destroying items and that's not ideal, but if you've got Cerberus Boots Assembled and your build is overall pretty complete in general, pulling the Lever is basically guaranteed to kill a lot of enemies without costing you anything you care about. (Caveat: if you'd still appreciate Exotic Mod Packs, you might be destroying one without realizing it... but these are rare enough it's unlikely) For a ranged build that hasn't permanently solved ammo, even if it destroys a bunch of ammo it can easily be the case that you're ahead on ammo by virtue of not spending tons on killing enemies.

But overall, I don't get why this isn't labeled 'dangerous' by Intuition 1.

While we're talking about Barrels: Barrels! The wiki says basic Barrels ("Barrel of Fuel") explode in radius 4 for 5d5 Fire damage (So 5-25 damage), Acid Barrels explode in radius 3 for 6d6 Acid (So 6-36 damage) with low-ish odds of leaving Acid tiles in each hit tile, and Napalm Barrels explode in radius 2 for 7d7 Fire damage (So 7-49 damage) with a very high rate of converting hit tiles into Lava. This largely matches to my experience except that I've found basic Barrels have a pretty noticeable variation in their blast radius, where sometimes being 4 tiles out doesn't get me caught in an explosion and other times being 6 tiles away isn't far enough to be safe. I also won't pretend to understand how the game decides to draw explosion radii when walls are involved: I'm constantly either being hit by an explosion turning a corner unexpectedly or surprised at an explosion failing to take a corner to hit me. Given the game's rules on line of sight/line of fire have some notable inconsistencies in general, I don't know if I'm just being caught out by that fundamental inconsistency or if explosions have some further oddities peculiar to them.

The wiki also says all Barrel types have the same HP (2) but different Protection amounts: 3/4/5 for fuel/Acid/Napalm. They pretty clearly work on the same rules as walls (Aside that they're 'fragile' and so can be damaged by any attack), as 2 shots from a weak hit doesn't necessarily detonate a given Barrel. My own experience is that the basic Barrels are the hardest to blow up, but I'll readily admit this could just be down to them mostly showing up early in a run when you're more likely to be using weak weapons and/or have inadequate Trait support (Son of a Bitch ranks, particularly) to reliably overcome even modest Protection values.

Water World

Intuition 2 Description: Floods with water.

Intuition 1 Description: Neutral

Effect: Every tile in the room (or map, if applicable) that isn't a door, wall, or occupied by a Barrel becomes water.

Level Feeling text: The air is really humid here...

To be honest, this probably should've been labeled 'beneficial' by Intuition 1. Flooding an area with water usually doesn't matter either way, but when Archviles are around the fact that corpses are eaten by water tiles can be incredibly useful, and on Nightmare! difficulty water is basically always a good thing unless you specifically want to grind an enemy for their ammo. It can also overrule Acid and Lava tiles, potentially allowing you easy access to a part of the map blocked off by them.

The only ways flooding an area with water can be negative for the player are if they want to grind a reviving enemy for ammo, or if it overwrites hostile fluids the player intended to use to hurt enemies. That's about it.

You might think I feel no Lever deserves the neutral description, and, well, at this point... yes. Yes I do. The neutral description is never really accurate in practical terms, and there'd need to be three or so Levers that do have it for the neutral description to be noticeably less precise than the Intuition 2 description. The fact that there's only two neutral Lever types means an experienced player already knows a 'neutral' Lever is either a water flooding Lever or a Barrel-detonating Lever. And if they pull a Barrel-detonating Lever and find another neutral Lever on that floor... the only possibility is that it's a water-flooding Lever.

Acid World

Intuition 2 Description: Floods with acid

Intuition 1 Description: Dangerous

Effect: Every tile in the room (or map, if applicable) that isn't a door, wall, or occupied by a Barrel becomes Acid.

Level Feeling text: In the State of Denmark there was the odor of decay...

This overlaps enough with the following Lever I'm not doing a whole thing for this alone; aside the possibility that you have the Acid Spitter and/or immunity to Acid but not Lava or vice-versa, it's just the next one but less dangerous.

Lava World

Intuition 2 Description: Floods with lava

Intuition 1 Description: Dangerous

Effect: Every tile in the room (or map, if applicable) that isn't a door, wall, or occupied by a Barrel becomes Lava.

Level Feeling text: You feel that smell? That gasoline smell? Oh hell...

I'm not a fan of the effect these Lever types have on gameplay.

In broad terms, these Levers are somewhat important in that Lever design -particularly how Intuition 1 works with Levers- only makes sense if there are bad Levers a player really should avoid pulling. If no such Levers exist, the player might as well pull every Lever they encounter, and Intuition 1's Lever benefit is worthless and Intuition 2's only slightly optimizes a player's usage of things like Meditech Depots. So there does need to be Bad Levers.

But I feel that Acid and especially Lava flooding is a bit too far in that direction. For an inexperienced player, they're that classic 'hardcore roguelike' experience of 'you died to an absolutely bizarre thing you had no way of anticipating occurring basically out of nowhere, where if you know how it works it's an avoidable threat but the only way to figure it out through in-game resources is to get killed by it repeatedly until you figure out the rules'. There's a reason most modern 'roguelites' don't recreate that particular aspect of roguelikes! It's almost never good design!

Even once you do know about the flood Levers and know how they work, they're... not great. Part of the problem is that -especially before 0.9.9.8 added ammo dispensers- the overall best beneficial Levers were for HP restoration and Armor restoration. So one of the main reasons to consider pulling a Lever is if you're low on healing supplies and there's not enough Health Globes on a floor to top you off... in which case gambling wrong and having a Lever flood the room with death is, even if you take appropriate measures (Start Running before pulling the Lever, only pull an unknown Lever if you didn't get either level feeling indicating a map-wide version exists, and only pull an unknown Lever if it's very close to a doorway), exacerbating the very problem you were hoping to correct. If you're already in good condition such that you can risk a really bad Lever outcome... the very fact that you're in good condition means you have little or no ability to benefit from the Lever!

Also not helping is that the game is allowed to generate multiple level feelings on a given floor and is unreliable about actually informing the player of extra level feelings when this occurs. I've never seen the game provide more than three level feeling messages at once, but have seen floors generate with 4 level feelings, and have at times seen two level feelings be announced and then had a third one existent that wasn't announced. As in, I've had times where the 'gasoline smell' level feel text didn't generate, and so I thought I was safe to pull Levers so long as I was careful about only pulling them when near a doorway and so on, and then my run was doomed because nope, Lava World time. I've yet to be screwed this way when only one level feeling got text, at least?

And no, this isn't just me having bad memory or something. 0.9.9.8 has added a feature where the character screen (Currently accessed by pressing 'p', previously accessed with '@') includes line telling you every level feeling-type announcement you got on entry in that floor. I've still had a run die in 0.9.9.8 where I checked that screen to be sure, saw no text for the gasoline smell, and pulled a Lever that promptly flooded the map with Lava. This is the game working funky, full stop.

Also wonky is that in the mid-to-late portion of an Angel of 100 run (And the comparable floor section of an Archangel of 666 run) often ends up flipping to flood Levers being pretty unambiguously good. If you've got Cerberus Boots Assembled (Or otherwise have permanent immunity to hostile fluids available), flooding a floor can kill most or all the enemies for free, and if your build is complete you probably don't terribly mind non-Uniques being melted. This ablates very late, especially as of 0.9.9.8, because boss enemies that can spawn late in those modes are all immune to hostile fluids, Elite Commandos are immune to hostile fluids, and in 0.9.9.8 all Nightmare variants of enemies are immune to hostile fluids, making a flood Lever less effective at killing enemies while still denying you items and possibly forcing you into a non-optimal switch. (ie slowing down heavily because you swap in your Cerberus Boots)

So overall I'd prefer it if at least the map-wide versions were just not a thing, and preferably these Levers were replaced with Bad For The Player effects that are less wonky. I'd frankly rather have a Lever that zaps Doomguy for 10 damage directly one time, as one possibility that would serve the core function without all this jank.

(You have no idea how tempting it was to break pattern and call the Lava Lever the Fire Sea Lever)

Rock Smash

Intuition 2 Description: Destroys walls

Intuition 1 Description: Dangerous

Effect: Destroys all the room's walls, excepting any that are part of the map border, setting them to the basic floor type for the level. (Map version simply extends this to every internal wall)

Level Feel text: You hear the trumpets of Jericho echoing in the distance...

I'm a little surprised the Intuition 1 description doesn't class this as neutral, but overall I'm glad it's classed as dangerous. While blowing open a room can be useful, such as if the floor has generated so you'd otherwise have to wade through Acid or Lava, it genuinely is the case that such a Lever is usually dangerous to pull. It can give enemies the jump on you, where you're suddenly attacked by several enemies where a moment ago nothing was in view, and broadly speaking terrain is usually to the player's benefit. It lets you corner-shoot, it lets you break line of sight from pursuit to lose them when necessary, control angles to limit how many enemies can fire on you at a given moment, and it lets you use the game's audio system to gather info on what enemies are roughly where without giving them opportunities to attack, potentially letting you make better preparations for what enemies are in the area.

The map-wide version of course cranks all this to the max: losing a room might mean you shrug and arrange to corner-shoot from a different spot. Losing all terrain means corner-shooting is simply not an option at all. Depending on your build it isn't necessarily all that bad, but it usually is bad. The main time it can be otherwise is if a floor has generated such that you can't get somewhere without wading through Acid or Lava and you don't currently have the tools to knock down walls...

... or the map rolled the level feeling that makes walls indestructible, as that level feeling does not prevent Levers from knocking down the walls. So that's one reason to start risking Lever pulls: trapped by indestructible terrain and a river of Acid? Maybe that nearby Lever will save you!

Or maybe it will flood the map with Lava and kill you.

Death Note

Intuition 2 Description: Kills creatures

Intuition 1 Description: Beneficial

Effect: Inflicts 20 Fire damage on all enemies in the room. (Or map)

Level Feel text: The smell of a massacre...

The room-scale version of this is frustratingly useless. Most rooms are small enough that you probably can't reach the Lever and have it hurt enemies without being visible to them and thus actively getting shot at, with larger spaces generally being attached to map types that bar Levers from spawning in the first place (eg Caves, Arenas) or that allow Levers but still won't spawn them in the larger spaces. (eg City floors are made up of a large open space, with rooms dotting the area with no connection to each other: you'll never see this Lever type in the large, open space where it could hit enemies on the other side of the map from you) Even if you're personally fine with charging for Levers in combat conditions and hoping for the best, the frailty of Levers means this will often just get the Lever destroyed, making your run for it actively counterproductive.

It's slightly better if you have Intuition 2, in that you can see what it is and try to bait an enemy into its room to kill them with the Lever, but it's still frustratingly prone to not mattering, especially if you're decent at corner shooting.

The map-wide version, meanwhile, is amazing to get early in a run and is still quite useful to occur later in a run. Many early-game enemies like Formers die instantly (Imps survive with 2 HP due to their Fire resistance, annoyingly), and even the toughest exceptions -such as Pinkies- will be trivial to finish off afterward. Later in a run, softening up Arachnotrons and the like is great, with essentially no disadvantage unless you're quite late in an Angel of 100 or Angel of 666 run -in such a case, you can end up with Elite Formers using Medpacks as a result of pulling this Lever. Every other enemy that can pick up Medpacks is either so frail the Lever will kill them, or so tough they won't drop below 50% and so won't use the Medpack.

It's a bit unfortunate that the map-wide version is really rare, while the room-scale versions are really common. Most of the time, the room-scale ones are essentially dud Levers. I get that the map-wide ones are powerful and purely player-advantaged, but honestly I feel like either the room-wide ones needed to be a bit more generous (Like spreading to adjacent rooms, if perhaps with weaker damage, or defining their radius by tilecount instead of rooms, allowing them to hit enemies even if their room is tiny) or for the map-wide version to be the only kind that occurs. (Maybe make the regular version 5 HP of damage while map-wide, so you can have a common-but-weaker variant?)

Regardless, this is one of the most dramatic (If erratic) benefits to ranks in Intuition, as you can see 'kills creatures' and just pull it and hope it's map-wide, and if it is, fantastic! Especially if this happens early: finding such a Lever on the second floor will sometimes result in an instant 'you feel relatively safe now', not to mention a level-up.

Incidentally, something that drives me up the wall is that there's a level feeling about smelling blood that, strangely, is one of the messages for a Special Level staircase being present. I bring it up here because I often get mixed up and think it's the level feeling text for the map-wide version of this Lever existing, because... yes? A massacre involves the smell of blood. I seriously doubt I'm one of a rare few to have this issue: I really wish this 'smell of blood' text wasn't around, or was reworked to something not so readily conflated with this Lever.

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Next time, we do a quick overview of difficulty effects.

See you then.