Doom Roguelike Enemy Analysis: Nightmare Imp

HP: 35

Protection: 0

Ranged Accuracy: +6

Melee Accuracy: +6

Ranged Damage: 2d6 Plasma

Blast Radius: 1

Melee Damage: 1d3 (+6) Melee

Speed: 115%

Inventory: Nothing.

Experience: 128

Danger: 6

Minimum floor: 30/27/24

Maximum floor: 60

Experience per Danger: 21.33

Can open doors. 50% resistance to Fire damage. Immune to Acid and Lava on the floor.

Evasion: ?? (The wiki says they're harder to Dodge than Imps, but gives no numbers)

Attack chance: 50%

The Nightmare Imp is our first example of a semi-standard enemy concept: a super-elite version of a regular enemy that normally doesn't show up in standard runs, but which you'll get pretty used to seeing if you do Angel of 100 and/or Archangel of 666. If you play on the upper difficulties, you can also see these super-elite enemies predictably in specific Special Levels.

I call it a 'semi-standard' concept because not every regular enemy has such an elite counterpart, not even out of lower-end enemies. There is no super-elite Lost Soul variant, for example. They're also not fully consistent with each other on various rules/elements -for example, most of these elite variants are 'Doom Roguelike originals' and don't have pain/death/random wandering audio, but some of them do have such audio, and some of them are arguably not invented by Doom Roguelike.

The Nightmare Imp is in fact an example of 'arguably not invented by Doom Roguelike', though this is probably non-obvious to a lot of players as Doom 64 is sort of poorly-known in the sense that plenty of people know it exists but plenty of people are unaware it's not just a port of classic Doom. Doom 64 introducing 'Nightmare Imps' is in fact probably the primary inspiration for the entire semi-standard concept of super-elite versions of regular enemies, as its Nightmare Imps are largely an Imp recolor with higher stats. Certainly, the palette Doom Roguelike applies seems to be trying to produce something akin to Doom 64's Nightmare Imp appearance, or more precisely to a cut feature from the Playstation port of Doom that could turn more or less any enemy into a 'nightmare' version and apply an automatic effect that modified their coloration, with beta screenshots showing that Imps affected by this ended up a dark blue like the sprites in this post.

Anyway, that mini history lesson thing aside, Nightmare Imps in Doom Roguelike are in fact one of the elite variant enemies that doesn't make noises. This is odd and unintuitive given that you'd expect them to just use regular Imp audio, but is also pretty light in its implications; regular Imps don't actually make noise all that often when wandering and share their random cry with all Former Human variants, so if Nightmare Imps worked the same as Imps it would be easy to be caught off guard by a Nightmare Imp regardless. (Both in the form of 'you didn't hear anything before it got close enough to see and attack you' and in the form of 'you did hear it, but figured you were hearing one of the other enemies that uses this audio and so were still not properly prepared when it got in sight')

The main implication of note in this regard is that it's easy to be unsure whether you actually killed a Nightmare Imp or not anytime your attack knocked it out of your vision. With a lone Nightmare Imp you can just keep an eye on the message log for the 'You hear the scream of a freed soul!' announcement, but if you are fighting a Nightmare Imp, typically that means a lot of enemies are about, where you can easily be firing into a crowd that includes enemies you've never even seen and so even careful counting of 'freed soul' announcements will result in you thinking you've killed everything in that area ("6 freed souls, I saw 6 enemies...") and in actuality there are survivors who just happen to be silent and so you also can't take 'I didn't hear pain or death noises' as proof that nothing is alive back there.

This is, kind of oddly, really the most notably interesting quality of Nightmare Imps, and I'm not sure why Doom Roguelike puts them in particular so late in spawn tables. Their statline is notably nastier than a regular Imp, yes, but if you compare a Nightmare Imp to a Hell Knight, the Hell Knight has more HP, hits just as hard with the same damage type with the same radius, gains a point of Protection, and is allowed to pick up and use Armors, Medpacks, and Phase Devices. The Nightmare Imp's only advantages are that it's 5% faster (Which is essentially nothing) and that it replaces 50% Acid resistance with 50% Fire resistance. (Which is overall an advantage given that the player has much more reliable, ready access to Fire damage than to Acid damage) So it's pretty weird that Nightmare Imps can't spawn in Angel of 100/Archangel of 666 until 9 floors after Hell Knights have been largely phased out; in raw game design terms, I'd expect the Nightmare Imp to be mid-early and essentially replaced by Hell Knights, not the other way around.

That said, within a standard run this doesn't matter. A standard run can technically go up to 25 floors deep and so it might seem like Nightmare Imps can spawn normally very late in a standard run, but the 24th and 25th floors don't use normal enemy generation routines at all in a standard run, so even up on Ultraviolence and Nightmare! it's not actually possible for a Nightmare Imp to spawn normally.

If you do see a Nightmare Imp in a standard run, you're either in Limbo (Where they contribute to the chaos of that Special Level) or are in the Phobos Anomaly on Nightmare! difficulty. (Where they provide a way for the game to amp things up just a little bit more compared to Ultraviolence without changing the 'character' of the floor too much; they're specifically replacing the regular Imps that spawn on Ultraviolence) Their usage in the Phobos Anomaly is actually pretty representative of how these 'super-elite' enemies tend to be used by a standard run; they show up specifically in non-standard floors, generally much earlier than their defined spawn depth (The Phobos Anomaly is floor 8; that's 16 floors early for Ultraviolence!), and mostly only if you're up on Nightmare! or Ultraviolence difficulties, typically directly replacing whatever they're an elite form of. (Also, a lot of them get randomly mixed into Limbo, especially if you go up on difficulties; this is one of the main ways Limbo is distinguished from The Mortuary, actually, as The Mortuary does not use these 'super-elite' enemies)

Within that framework, the Nightmare Imp's statline makes a lot more sense; it's not actually meant to be a super-late-game enemy, but a nastier version of a regular enemy so a certain non-random floor can be made yet harder on the highest difficulties.

It's only within Angel of 100 and Archangel of 666 runs that the 'basically a worse Hell Knight, but only shows up much later than Hell Knights' strangeness comes into play. This, itself, is pretty clearly a product of those modes being a bit tacked-on, or an afterthought, or however you prefer to frame the idea; the point is, Angel of 100 and Archangel of 666 aren't the 'core' experience the game caters first and foremost to, but rather are a side-mode that uses existing content in a manner it isn't necessarily designed for, and which the engine wasn't necessarily built to smoothly support refitting things appropriately.

That is, if the game wants an enemy to spawn in with the normal random monster generation rules in Angel of 100 and Archangel of 666 while not being allowed to randomly spawn into a regular run, the game has to set that enemy so its starting depth is noticeably past where a standard run ends, due to how the engine is set up. It's not set up so different modes can have different rules on monster generation; indeed, Angel of 100 and Archangel of 666 have some noticeable oddities like that floor 8 still plays the music that plays specifically on the Phobos Anomaly even though in those modes floor 8 isn't a special floor at all, because the engine wasn't really built with such alternate modes in mind as a possibility.

Nonetheless, Angel of 100 and Archangel of 666 prefer to make use of all enemy types; there's only a handful of enemy types that are completely impossible to see in such runs, and they can mostly be reasonably described as 'not really able to add anything'. I'll be talking about those as we get to them, but the relevancy here is that Nightmare Imps are in a strange place in Angel of 100 and Archangel of 666 runs because they're meaningfully unique enough to justify inclusion but their intended usage coupled with the engine limitations means that their inclusion can't really be tuned properly-appropriately.

Which is all unfortunate, and was one of the sadder things about the development going on hiatus for so long. (Though with 0.9.9.8 having hit, I guess now it might be corrected?)

Anyway, I should call attention to the unexpected detail that Nightmare Imps do Plasma damage where regular Imps do Fire damage. I'm not a fan of this detail, personally; by default it's a straightforward improvement in their effectiveness, but in conjunction with the player's ability to equip for specialized resistances it creates a bit of a trap, where a player is liable to assume a Nightmare Imp is an upstatted Imp, and for most purposes this is accurate, but then if the player does something like prep with a Fireproof Red Armor in expectation of Fire damage they'll unexpectedly die rather quickly since the Nightmare Imp isn't doing Fire damage at all. A player could easily die to this multiple times without understanding why, too, since damage typing isn't communicated all that strongly by the game.

Especially frustrating is that Nightmare Imps do in fact throw the same fireball sprite as regular Imps, with the same audio; just using the Cacodemon blue fireball would do a lot to point a player in the right direction.

Once you do know about Nightmare Imps doing Plasma damage, it's pretty easy to adjust your preparations appropriately... assuming you don't forget...

... it's really not ideal...

... anyway, that aside, unless you're specifically encountering them at the Phobos Anomaly by virtue of doing Nightmare! difficulty, Nightmare Imps only show up late enough their stats are pretty mediocre relative to everything else running around, so even the above jank can end up just not mattering. If you're already equipped with your endgame gear that makes you nearly invulnerable to everything and able to shred even bosses in no time flat, Nightmare Imps are probably almost beneath notice.

I do wish Nightmare Imps were fit a bit better into the design in general, honestly. Fortunately, they're probably the worst off of the 'super-elite' enemies as far as this goes; the other examples overall work much smoother than this. (Though still with jank, particularly in Angel of 100 and Archangel of 666 runs... but seriously, less jank)

0.9.9.8 has adjusted Nightmare Imps moderately. Firstly, it buffed their Accuracy in melee and at range, taking it from +4 to +6. (So for one thing they're not so purely 'worse Hell Knights') Oddly, the patch notes also claim they were made faster, but... no? They were already 115% Speed.

More janky in patch note presentation is that 0.9.9.8 says Nightmare enemies of all types are now 'resistant' to floor effects... which is a really strange word choice for attempting to convey 'completely immune to Acid and Lava on the ground'.

In the case of Nightmare Imps, this is kind of a mixed bag. On paper, it's pure improvement to their threat profile, but in standard runs I'd say it overall makes things easier. In the Phobos Anomaly, it doesn't matter unless the player somehow has the Acid Spitter already. (Which I don't think is possible) In Limbo, though, it results in Nightmare Imps being spawned by Archviles off on the other side of Lava and trickling over to Doomguy and pretty much inevitably dying on Lava so they can't be reanimated. So... it makes Limbo easier, generally speaking.

It's slightly more coherent for Angel of 100/Archangel of 666. It can still backfire in basically exactly the way I just described, but it can also result in greater difficulty shaking pursuit, where eg a Nightmare Imp spots Doomguy from across a Lava river, and when Doomguy walks far enough away that he's out of sight of anything on the other side of the river, the Nightmare Imp just follows him across it and keeps pelting plasmaballs. Though they also can't show up before Archviles are common, so much like with Limbo, their new immunity makes them more prone to avoiding being revived... and this gets so much worse if you're up on Nightmare! difficulty.

... to be honest, I feel this sweeping 'Nightmare enemies are immune to floor hazards' decision is probably a mistake for a variety of reasons...

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Next time, we move on to another 'super-elite' enemy: Nightmare (Pinkie) Demons.

See you then.