Doom Roguelike Enemy Analysis: Cyberdemon (0.9.9.7/0.9.9.8)

HP: 210/240/290/360/450 (Base of 200, plus 10*difficulty number squared)

Protection: 4

Ranged Accuracy: +12

Melee Accuracy: +8

Ranged Damage: 6d6 Fire

Blast radius: 3

Melee Damage: 1d3 (+15) Melee

Speed: 110%

Inventory: Rocket ammo*30, plus their Rocket Launcher

Experience: 2720

Danger: 30

Minimum floor: 80/77/74

Maximum floor: Infinite

Experience per Danger: 90.66

Can open doors, equip Armor, and pick up and use Medpacks, Phase Devices, and Homing Phase Devices. Immune to Acid and Lava on the floor. Sees 2 tiles further than normal. (ie 10 tiles). Takes no damage from its own rockets. Has to actually alternate reloading and shooting.

Hunts Doomguy precisely. Fires on Doomguy even if line of sight is blocked, so long as Doomguy is in the radius defined by its base line of sight. (ie 10 tiles) Immune to knockback.

Evasion: Base of 30%, +5% per tile of distance, making for a maximum of 70%

Attack chance: 75%

The wiki has spent all these years claiming the Cyberdemon is only immune to knockback in the Tower of Babel (ie floor 16) and thus can be knocked back in Angel of 100/Archangel of 666 runs...

... and this claim was wrong in 0.9.9.7 and remains wrong in 0.9.9.8. Maybe it was true in a prior version I've never tried, but I also wouldn't be surprised if it was intended but was never correctly implemented and the wiki is going off dev intentions rather than actual in-game behavior, or something of that sort.

That said, it does have a behavior change between the Tower of Babel vs outside it: audio! In the Tower of Babel, every time the Cyberdemon moves a tile within standard hearing range, you hear a metal clank, representing its cyborg leg hitting the ground. (With enough experience, you can in fact pretty accurately guess its distance based on this sound, as Doom Roguelike does have a reliable 'fading' on more distant noise sources) It also uses a unique audio clip when killed in the Tower of Babel, and rather oddly has no pain noise.

If you're not in the Tower of Babel, Cyberdemons do not make noise as they move about (Including that they don't do the usual intermittent growling behavior most enemies have), but have Hell Knight pain and death audio for their own pain and death clips. This makes them surprisingly rude in Angel of 100/Archangel of 666 runs, as they will charge straight for Doomguy and typically your first sign that a Cyberdemon is about is a rocket flying out of the shadows!

Anyway, in a standard run you encounter just one Cyberdemon, specifically in the Tower of Babel, which is to say floor 16. The Tower of Babel is weird in a number of ways, starting from the fact that there's basically nothing in it; the Cyberdemon is the only enemy on the entire floor, and there's absolutely no items. Just a randomized smattering of pillars providing inconsistent cover. It also is odd for having an exit staircase you're not actually meant to use: it's always hidden inside one of the pillars and can be used if the pillar gets blasted open, but you're intended to kill the Cyberdemon, which will instantly whisk Doomguy away to Hell 1, the 17th floor. (Well, I say 'instantly', but there's text marking the transition. But my point is that, unlike the Bruiser Brothers, you don't manually find and use an exit) Unless you're doing Angel of Pacifism, of course, in which case there's an exit staircase in the open and you are intended to run for it.

Also weird is how this is a special floor, but it's actually pretty heavy on randomness. Doomguy's start position is randomized, the pillar placement is random (So much so that pillars can overlap into messy formations), and even the Cyberdemon's starting position is random! It is in fact possible to hit the floor and have the Cyberdemon in immediate view. It's unlikely, but totally possible.

The Tower of Babel is notable for being one of the few parts of the game's design where corner-shooting doesn't dominate and you really ought to do what the devs seem to have originally intended to be broadly smart play; Dodging shots and pumping the Cyberdemon full of holes while it's reloading before deftly sidestepping the next rocket. After all, the Cyberdemon is perfectly happy to fire on Doomguy even if its line of fire is blocked, and its rockets will not only quickly smash the pillars so they can't hide Doomguy but also Doom Roguelike's explosion behavior is such that a shot blocked by a pillar can still end up propagating its explosion onto Doomguy and so you take damage regardless. Since it will happily open fire on Doomguy from beyond your own maximum line of sight, running up behind a pillar and waiting for it to come into view to start corner-shooting is likely to result in it just blasting you to bits without ever entering line of sight, especially since its attack chance is quite high and reloading is an extremely high priority for it. (By which I mean that if it fires, it doesn't have a 25% chance of advancing on the following turn, because it will reload)

Partly as a consequence of the poor viability of corner-shooting, the Tower of Babel ends up being oddly like a 'stat check' or 'build check' or however you want to put it. That is, a lot of classic Roguelikes are designed so that there's some minimum threshold of your character's capabilities you ideally meet before taking on certain challenges (eg in Angband you ideally have various key resistances online before descending to floors that risk 'It breathes. You die.'), and this type of design is in fact something games shooting for the classic Roguelike sort of design tend to clearly prize as an important part of classic Roguelike design. (I keep saying 'classic', because more recent Roguelike/'roguelite' designs have skewed heavily toward using procedural generation to support high replayability in the form of many comparatively short sessions, and quite often these games skew a bit more toward good judgment and possibly 'twitch play execution' rather than 'stat check' design) Thanks to the corner-shooting bug having been enshrined as a feature, Doom Roguelike doesn't skew that far in that direction: so long as your ammo doesn't run out, Doomguy can stand in place and kill enormous numbers of enemies, even if individual examples would murder him if he tried to fight them in the open, just by using corner-shooting.

Whereas in the Tower of Babel, it's entirely possible for your build to be sufficiently understrength you just... auto-lose the fight no matter how well you play. For example, I've had a fair few Angel of Shotgunnery Shottyhead Scouts that breeze through Deimos by just using a Tactical Shotgun on everything, enter the Tower of Babel with 150+ Shells, and then run out of ammo, flail ineffectually in melee, then die.

Part of what underlies all this is that the Cyberdemon is a big slab of stats. Even on I'm Too Young to Die it already has a monstrous 210 HP, and 4 Protection is a lot. For example, that Tactical Shotgun scenario I just laid out expects to average around 12 damage for the roll... except you'll lose some damage to range drop-off... and you'll lose 8 damage to the Cyberdemon's 4 Protection... so if you close to range 2 and keep shooting from that range and Dodging the Rockets you're expecting to do 3-ish damage most pulls of the trigger. That's expecting to spend 70 Shells to kill the Cyberdemon on the bottom difficulty! If you're up on Ultraviolence, you instead expect to spend around 120 Shells if you're always firing from range 2!

Notably, if you're firing from farther, your expected damage rapidly deteriorates to 'constantly do 1 damage'. At that point the 360 HP it has on Ultraviolence expects to eat, well, 360 Shells. It's not necessarily obvious that it's important to get pretty close to overcome its Protection, so I imagine there's quite a few players who have run into this issue without understanding why they ran out of ammo and died even though they had almost 400 Shells. Or did kill it, but were left so low on ammo they died on the very next floor from running out of ammo.

Other ranged weapons hold up better than Shotguns do, mind, but they can still easily chew through a  concerning amount of ammo. A Chaingun backed by Son of a Bitch 3 fired at line of sight averages roughly 3.5 damage per bullet while missing half its shots; that expects to spend a bit over 100 bullets to kill this one enemy on Ultraviolence. Getting moderately unlucky and spending 150 ammo instead isn't shocking. And yes, an experienced player will presumably try to get closer before shooting, but part of my point is illustrating that it can be rough when playing to a build's strengths; imagine our Shottyhead Scout responded to getting low on Shotgun ammo mid-late in Deimos by picking up a Chaingun and 10mm ammo to use on the Cyberdemon. In that case, the Chaingun will do 1-2 damage per bullet, since our Shottyhead Scout presumably doesn't have Son of a Bitch ranks; even if I assume this is an Angel of Max Carnage run so (almost) every shot hits and always rolls max damage, that's 180 bullets spent to kill the Ultraviolence Cyberdemon! In a standard run, it'll probably be more like twice that, very possibly noticeably over twice that depending on damage and Accuracy rolls; bringing in 400 bullets because your Shells are running low might not be enough!

The flipside to my 'stat/build check' commentary is that it's absolutely possible to breeze on through effortlessly with the right gear and/or build. Melee builds especially just need to zig-zag until they're in range and start swinging; only Malicious Blades is particularly impacted by 4 Protection (And even it isn't hit that hard), and melee builds are all equipped to pretty quickly shrug off the Cyberdemon's 16-18 melee damage. (By Berserking providing 60% Melee resistance or by virtue of the innate 75% Melee resistance for leveraging Malicious Blades) Similarly, Shotgun runs that get a Nano-shrapnel Shotgun online are not in any danger so long as they remember to sidestep the rockets, and even Plasmatic Shotguns or Plasma Shotguns can typically get through pretty easily. And of course Nanomachic weapons render the ammo efficiency point moot; a Nanomachic Chaingun might be slow to kill the Cyberdemon, but so long as you don't get killed, you'll eventually win.

Overall, I think the Cyberdemon fight in the Tower of Babel works out pretty well, and it's certainly ahead of the Phobos Anomaly in design when it comes to the consideration of different difficulties (Well, aside the oddness of it being a fixed Danger and experience payout for every difficulty; on I'm Too Young to Die, the prior floor was 39 Danger vs the Tower of Babel being 30 Danger. On Ultraviolence, the prior floor is about 77.5 Danger, while the Tower of Babel is still 30 Danger), but it's got some rough elements. The Cyberdemon's 4 Protection in particular has implications I'm not a fan of in context... but while it is frustrating to at times just run out of ammo and die, I overall think it's the best-designed of the bosses.

It's also probably the most interesting boss to have guest-appearing as a regular enemy late in Angel of 100/Archangel of 666. For one thing, dropping it into regular floors interacts interestingly with 'hunts Doomguy precisely' and 'fires on Doomguy if he's in range regardless of whether he's properly in view', because it will get more opportunity to do things like simply blast its way into a room Doomguy is in, which no other enemy will do as an intentional act. Similarly, its ability to unexpectedly contribute to an ongoing fight from out of view is potentially pretty nasty! It also gets more opportunity to show off its immunity to fluids; in a standard run, you have to have the Acid Spitter or Napalm Launcher for the point to come up, whereas in Angel of 100/Archangel of 666 it can wade through a river of Lava to get at Doomguy in circumstances that eg a Revenant would be stymied by. And the immunity to knockback gets more opportunity to be an interesting quirk.

Though I should point out that, just like Bruiser Brothers, the Cyberdemon being allowed to pick up and use gear is more or less irrelevant since it has the 'hunts player precisely' AI flag. It's actually kind of funny the Cyberdemon is flagged to use equipment given its normal usage would have it irrelevant even if this AI point weren't true; there's nothing in the Tower of Babel to pick up! But even in Angel of 100/Archangel of 666, it's more or less impossible to see a Cyberdemon picking up gear.

Anyway, it also is one of the bosses most deserving of its extremely late placement in Angel of 100/Archangel of 666. It still tends to work out to being not that big a deal by the time it's allowed to appear, as such runs are often outrageously durable and deadly by that point, but if Cyberdemons could just spawn in at like floor 50 that would be genuinely pretty rude of the design, so their late placement is very understandable. I'm mostly commenting on it because I find it pretty funny how the 'single-monster level' floor type's message for an all-Cyberdemon floor plays them up, with Doomguy feeling an urge to scream in TERROR (All-caps in-game, to be clear), whereas the handful of times I've gotten that floor type, it was always a breeze. Sometimes moderately annoying in terms of multiple Cyberdemons ping-pinging me around so I can't stay focused on one target (and/or slowing down a melee build's ability to get into melee with one of the Cyberdemons), but never notably dangerous.

Nightmare Arachnotron caves are usually much more deadly.

Oh, and I should point out that the Tower of Babel has a unique tune that plays over it that sounds quite different from all the regular floor tunes. Just like the Phobos Anomaly, this extends to Angel of 100/Archangel of 666 runs, where floor 16 plays this tune even though it's just a regular floor in those runs; I've been startled by this on several occasions, honestly!

I should similarly point out that, if killed in the Tower of Babel, the Cyberdemon generates visuals and audio for a massive explosion, but this has no mechanical significance: the Cyberdemon can't take you with it in death.

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Next time, we cover the earliest Hell boss, the Angel of Death.

See you then.