Doom is so much more disturbing than Quake. 

No maps from 'blood' nominated? 

The whole game emits smell of evil, yet tasteful...

I'm still haunted by the theme...how I wish I could use a "blood" icon here... 

Totally evil. The buildup to the first encounter is great. 

Also the Zer DM maps 

'Temple of blood' from Zer

hell-ish doom maps were just garish
and scrolling textures made me dizzy :[

blood was fun 

I clicked this topic expecting something along the lines of "what are the hardest, most teeth-gnashingly frustrating maps ever?", and I was all ready to trot out the usual suspects, but I see we're discussing *evil* in the traditional sense :}

In that case, I'd have to say Doom3 is a good candidate. Melty-face-in-the-mirror, Crucified-maggot-room-guy, all the evil whispers and visions, the way the whole Mars base falls apart into hellish chaos as you get further into the game, and of course Hell itself.

It is also worth mentioning the final return to what what once the Delta Labs in the RoE missionpack. Something about that map fucked my shit right up. 

The singlemost chillingly evil atmosphere of any map I've played, was the 'garden' section in System Shock 2. 

The mansion in Undying was pretty twisted.

Blood didn't seem all that evil to me. I felt it was more like a disturbing cartoon. Still pretty nasty, though. I'd love to see that theme pulled off successfully on today's--or even yesterday's technology. 

that house that you go in with all the flesh growing everywhere was pretty wicked, in particular. 

The Zerst�rer maps for Q1 were probably the most "evil" maps I've ever played in my life. Resident Evil 0 for the GC although very different, comes pretty close too. Oh, and obviously Doom episode 3 and Ultimate Doom episode 4. 

...in System Shock 2 was freaky but perhaps not evil. Or maybe it was considering what it was made from...

The Funhouse secret map in Blood 'Over the Teeth - Over the Gums - Lookout Tummy - Here I Come' is one never to forget (and the Carnival with head punting that preceded it.) What carnival or funhouse isn't evil.

The Insane Asylum in Painkiller. Much evil was done to those poor patients. Nasty place.

But for visceral gore, DooM is way up there. Q1 has some bowel rippage texs too but they're underused.

Undying needed a truly evil freakish setting to live up to the Clive Barker imagination but sadly didn't despite being pretty good overall. 

The Carnival. Mere words and exclamatory remarks do not do this map justice. My only regret--albeit faint--is that the audio track is a fast-paced chaotic piece instead of a creepy track of children moaning and singing unintelligible rhymes while cultists lure them away a la The Pied Piper, such as we hear in the first 15 seconds of the track. Yes, this would have been pure, painful bliss.

Fresh victims for the ever-growing army of the undead. 

I assume we're talking about FPS levels here, in which case I'm off topic, but Silent Hill 3 (the only one I've played of the series) scared my pants off. 

These 2 games have also very evilish levels, with lots of zombies, cemetery, lava, dragons, etc... and a very good heavy metal soundtrack... 

that house with the babies at the ceiling
oh my god, that was scary!

and vampire2, the haunted house quite at the beginning of the game! 

Just how the hell have I managed to forget one of the scariest games ever: Alien vs. Predator 2! Whilst the alien and predator campaigns were just plain good, the marine campaign of the game was one of the best singleplayer experiences I've ever had: eerie, spooky and scary as all hell. 

thats why I cant wait to play FEAR. Oooh its gonna come tomorrow morning I hope! 

the marcher fortress' bell tower was nice... I mean.. doom-bringing. For whom do they toll? 

that summons thee to heaven...or to hell 

He that hoots and chirps--who tolls his wing'd bell? 

CZG07c was beautifully diabolical and all of that blood (the waterfall of blood for example) was great. That and the open layouts reminded me of doom a lot. The maps that it inspired, such as Necros' were also good.

I know how lame this sounds but I found Doom3's hell underwhelming in comparison to the Ultimate Doom's.

Quake 3 had some nice evil moments though. I remember looking at some early screenshots and thinking, "They're using shamblers... as parts of their maps!" 

I clicked this topic expecting something along the lines of "what are the most _evil_ Q1 SP only maps ever because that's the only thing of interest". But it ain't, so GG Tronyn, although I'm not sure what more I can add to what others have posted...

Zerstorer. Not much more needs to be said.

Some bits of Undying. Scary and atmospheric and generally cool.

Some bits of Painkiller. Silly gameplay but a few of the maps had a proper evile style.

Doom3. Well the maps weren't particularly evile and I found Hell a bit underwhelming, but some of the atmosphere and stuff was spot on. All the bits with organic shit infesting the base in particular. Probably the scariest game I've played.

Some bits of Wheel Of Time. Shadar Logoth and the dark fortress near the end, definitely creepy.

Some bits of Alice had an evile vibe.

A few maps in Daikatana E3, Enclave, Blade Of Darkness and maybe FAKK2. I can't remember much but most such themed games have one or two evile maps.

Custom maps I really can't remember, I know there have been a few around. I actually found Masque quite evile.

Ummm yeah.