Doom Roguelike Enemy Analysis: Shambler (0.9.9.7/0.9.9.8)

HP: 85/100/125/160/205 (Base of 80, plus 5*difficulty number squared)

Protection: 3

Ranged Accuracy: +4

Melee Accuracy: +4

Ranged Damage: 4d5 Plasma

Melee Damage: 1d3 (+8) Melee

Speed: 100%

Inventory: None.

Experience: 608

Danger: 14

Minimum floor: 80/77/74

Maximum floor: Infinite

Experience per Danger: 43.42~

Can open doors. Regenerates 1 HP every action it takes. Has a 16% chance each turn to randomly teleport somewhere nearby Doomguy. Immune to Acid and Lava on the floor. Projectile pierces all non-terrain entities, and is incapable of inflicting knockback.

Attack chance: 75%

The Shambler is apparently a Quake reference, which as of this writing remains That Classic Id Game I've Heard Of But Never Experienced, so I'm not going to pretend I have any idea how accurate it is.

I will comment that I'm doubtful its exact soundset is accurate to its source, as all its noises are just classic Doom noises, but in a weird mix that seems unlikely to be what Quake itself used. Its ranged attack uses the same demonfire-throwing sound as eg Imps and Hell Knights (Except it has no impact sound at all, strangely), it uses the Baron of Hell cry, and it uses the Arachnotron death sound when killed. Furthermore, it doesn't have any sound assigned for when it's being hurt. (Oh, and when it teleports it uses the classic Doom sound for teleporter usage, but that part seems perfectly reasonable and my only question is 'does classic Quake recycle that sound for teleportation?')

Whatever is going on with the reference, the Shambler itself is the earliest possible Deimos boss, and is several bits of weird.

There's the teleport, to start, which... I should probably talk about the default context, honestly.

In a standard run, you will encounter a Shambler exactly once, in either Hell's Armory or the Deimos Lab. Only, well, the Deimos Lab has two of the things... but the point is, you do a whole Special Level adventure that has special loot, up to and including Exotic Mod Packs at the end. One of the more subtly odd aspects of this whole thing is that no Shambler is on the map at the start of either of these Special Levels; the game pretends like you're releasing one or two Shamblers, with Deimos Lab in particular being designed so you can throw its four switches, see the terrain in the middle of the island disappear, and run over and see that the Shamblers are inside the zone you just opened up, but in actuality you spawn the Shambler(s) through throwing the relevant switch(es). You can tell this pretty readily since the 'you feel relatively safe now' message can in fact fire by clearing the map before pulling the relevant switch(es).

This is important, since Shamblers do have their teleport, can do it on any turn, and always try to teleport somewhere nearby Doomguy. I'm mostly confident they teleport specifically into vision range, but that's 'vision range' as in 'somewhere within 8 tiles', not 'somewhere where they can see Doomguy' nor 'somewhere Doomguy can see them'; they're perfectly happy to disappear behind a wall. Anyway, point being they can't be a climactic confrontation at the end of a Special Level by just locking them up the way the game does to the Bruiser Brothers, so it has to do shenanigans where it spawns them in.

The teleport itself is a pretty funky aspect to their design in practice. They do it totally randomly; they don't use it to intentionally pursue or intentionally escape or anything like that, and their destination is similarly selected quite randomly. This means they can use it in pretty nasty ways, or they can pointlessly waste a turn teleporting to a position 2 tiles away that is in no way advantageous over their current position or in fact is pretty clearly worse than their old position. Indeed, corner-shooting is usually very effective against them, as they're prone to closing in and then teleporting away since there's just... more possible destinations further from Doomguy than near to Doomguy.

That said, there is their regeneration to consider. 1 HP per turn doesn't sound like much when you consider a Shambler has 85 HP at minimum and can have up to 205 HP on the highest difficulty; on Ultraviolence, they're regenerating 1/160th of their HP per turn... so not even 1%.

But! Their teleportation can easily result in them buying themselves several turns to regenerate in; this happens pretty readily and pretty dramatically in Hell's Armory if you try to cornershoot the Shambler from one of the doorways right on top of the lever that spawns it, but in Deimos Lab it's still plausible for a Shambler to jump to the other side of a wall and so buy itself 5+ turns of healing. Furthermore, Shamblers have a rather high Protection stat at 3; for Shotgun builds and rapid-fire builds that aren't able to turn a Plasma Rifle on the Shambler(s), that's very noticeably ablating your ability to get damage through. (You do generally expect to be able to use a Plasma Rifle, mind, as both Hell's Armory and the Deimos Lab provide reliable sources via Former Commandos) Doing 20~ damage only for a Shambler to teleport away and spend 5+ turns protected by terrain can draw the fight out a fair amount if it keeps happening.

Their ranged attack is also exceedingly odd, particularly in the context of a standard run where you're expected to be fighting just one or two Shamblers with everything else dead. (Unless you're up on Nightmare! and not cleaning up corpses, I guess) Its Railgun-esque penetration isn't a beneficial quality for them, as Doomguy himself is the only thing they'd want to hit, so all the penetration adds is the potential for friendly fire. A potential that will rarely be realized if you're doing a standard run and make the effort to clear out the map first. And frankly, it's not even all that likely to come up in Angel of 100/Archangel of 666 runs, as Shamblers are prone to teleporting atop Doomguy so quickly he may not have gotten to fighting any other enemies, and the map may well be designed so they're jumping Doomguy in an enclosed environment and so can't hit their allies in the darkness.

I'm also not a fan of how the twin points of 'no impact sound' and 'projectile doesn't stop if it hits' takes away the primary feedback mechanisms regarding whether you're taking damage or not. With most enemies, you can pay attention to the animations and accompanying audio and instantly know that the three Baron acidballs sent your way missed because they went right through Doomguy and exploded beyond him. (Notably, it's possible to not hear an impact sound from such enemies, but only if they miss so the shot can go impact somewhere out of Doomguy's sight) With a Shambler, you must look at your HP to check if a given shot hit or whiffed. It's not great.

This is exacerbated by what is otherwise a mercy; that the shot can't inflict knockback. If knockback was possible, a lot of successful hits would inflict knockback and so you'd know those were successful hits right away. This would be unreliable compared to the other points (negated by Badass, for one), and I don't want Shamblers to inflict knockback given they're a pretty nasty enemy and are intended to be fought with your immediate surroundings having either Acid or Lava tiles to potentially be knocked into, but it does contribute to the jank.

I should also put attention on the Shambler's attack chance. I imagine most players subconsciously pick up on the fact that most enemies are actually pretty prone to spending their turns advancing on Doomguy rather than lobbing fireballs, with zombies as the main exceptions, and Shamblers broadly fit into the same sort of profile as a Baron of Hell, including having the same audio for their ranged attack... but will spend most of their turns attacking, unlike a Baron of Hell. The teleport chance does at least seem to preempt the attack chance, but it's very normal for a Shambler to spend a dozen turns not performing regular movement, firing or teleporting every time. As such, even though their 'on paper' damage isn't really that different from a Baron of Hell (Same damage roll, bumped up by Plasma ignoring half your Protection, but on the other hand their Accuracy is one point lower), in practice they're usually much more lethal than a lone Baron simply because they keep attacking. As the attack chance mechanic is not communicated by the game at all and isn't terribly intuitive, it's easy to thus underestimate a Shambler's damage throughput because on some level you recognize that most enemies don't tend to fire 3+ turns in a row and are subconsciously expecting the same from the Shambler, unaware this is quite wrong in its case.

For reference: a 40% attack chance will fire three turns in a row only 6.4% of the time. (This is the Baron of Hell attack chance) A Shambler's 75% attack chance will do so 42.1875% of the time if we ignore its teleport chance. That means a Shambler is nearly seven times as likely to attack three turns in a row than a Baron of Hell!

In an Angel of 100/Archangel of 666 run, Shamblers become overall more convenient than threatening. If you got far enough for them to start spawning at all, you're probably outrageously lethal and durable and aren't menaced by much in general; having them teleporting atop you just speeds things up.

Though I should point out that they have an actual corpse. In a standard run, this is only important if you're up on Nightmare! and even up there it's pretty easy to end up killing them over Acid or Lava so the point is rendered moot, but in Angel of 100/Archangel of 666 this can result in you killing a Shambler or three, wandering off, and abruptly have seemingly-new Shamblers teleporting atop you, because an Archvile or Nightmare Archvile resurrected them. That can be an unpleasant complication if it occurs while you're already embroiled in a fight...

That said, since they're immune to Acid and Lava on the floor and can't show up until so late that it's common for a floor to be pretty heavy on Lava, it's still pretty common for the potential for revival to be rendered moot by them dying atop a river of Lava or the like. Especially thanks to another source of Lava we'll be covering later...

Overall, aside the jank with it being easy to not realize Shamblers are in fact hitting you successfully, I think they work okay, but man is that jank frustrating.

Oh, and I should point out that Deimos Lab and Hell's Armory both hide a pair of Supercharges beyond hazardous fluid. In Hell's Armory's case, they're to the west, right behind the wall block that you'll get Mod Packs and a Schematic out of once you kill the Shambler, while in Deimos Lab's case they're on the east side of the map, beyond a cache of weapons. The latter one is overall more convenient, as it's possible to blast your way through the wall without too much effort, in addition to Acid being safer to wade through than Lava if you don't already have immunity to fluids. (Which you probably don't at this point in a run, outside Envirosuit Pack usage) These Supercharges are one of the few bits of Doom Roguelike hearkening back to classic Doom's tendency to reward curiosity and inquisitiveness with mechanical payoffs; the Roguelike framework is admittedly not a great fit to that type of design, but I'm always surprised by how even Special Levels don't do this much.

Also, to my surprise, 0.9.9.8 doesn't seem to have changed Shamblers at all. Mmmmmaybe their sprite is slightly larger? I'm not sure I'm not imagining that, though.

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Next time, we cover the second Deimos boss, the Agony Elemental.

See you then.