Attached is a pic from Doom's custom map "Welcome to Hell", running under Doomsday engine.

I found it on THIS Hungarian forum, that hosts engine remakes for such oldies as Doom, Duke Nukem 3D, Hexen, and high texture packs for, say Deus Ex 2 and Thief 3. There's even a 3D engine for Wolfenstein. Nuts.

Saves a LOT of searching the web. You have to register to view it, though, but it's worth it. Also, don't mind the Hungarian, you don't have to know it to understand what's going on.

Doomsday's quite nice indeed.

Ok, let's see. The blood effects are really nice, but could use a better texture. Blobs just dosen't cut it for me :p

I couldn't get the 3d models to work, but I'm sure it'd be amazing.

Multiplayer is barren. Like, really barren. ZDaemon has a lot more people playing, and automatically downloads custom iWADs, so my vote goes for that.

Everything is glowy, which is good. But a lot of things are blurry, but maybe that's because I ran it with OpenGL.