Doom

Oh yeah, I must say that I am quite the fan of Doom, although I am unsure about it being "flat" (Doom that is - not the Earth, that IS flat), from what I recall, people say that Doom is what is called "2.5D", unlike Wolf 3D that is more flat, idk.

One of my favorite mods for Doom is probably going to have to be 900 Deep in the Dead, a banger of a level pack that I play way too much - I really wish that there was more maps by the guy who made it, it really is a same cuz 900 Deep is great, plus it can be played in DOS due to it being what is called "vanilla". I would really check it out as I do love it: www.doomworld.com/idgames/levels/doom/0-9/900deep

I mean, it _is_ a bop, so that is a good pick

Okay, well doot is quite funny, but I would have to say that E2M2 wins due to the fact that I seem to play that level a lot of the time, plus the music is really good, sounding quite creepy at times (Bobby Prince, IMO did a good job at making the music in Doom). The song used in this level is called The Demons From Adrian's Pen, a good remixed version of the song can be found here by Ctrl+F'ing on the page itself.

What also makes the level really fun is that you get a berserk pack almost once you start the level, allowing you to make the monsters in the map go SPLAT, plus this is helped by the fact that there are no hitscan monsters in the level to ruin your day.