other songs in Doom are e.g. E3M1 -> "Mouth For War" by Pantera. or E3M3 -> "Behind The Crooked Cross" by the evil SLAYER...
the songs are rearranged in such a funny way -> starting off exactly as the original and then slowly transforming into something more approbable for the game.
the soundtrack of the Doom-games is still a terrific enhancement for the mood of the whole game ... I love it.
btw...yesterday we played the leaky by a friend (ab)using his sony-projector and Xp and ... it was amazing. but the spare use of enemies is way too boring! the only scenes that stuck out were in e3_1 at the beginning(zombies) and in e3_3 the scene with the staircase where the ragdoll-fatso comes down and after him 2 imps.
I'm not judging the leaked 1Gbyte shadowmaker but I hope the final stuff gets much more hellish, organic and monster infested...

have fun