INTRO - Keep as it is. Intro will not be touched!
SPEC1 - Barrels O' Fun, obviously! No other question here.
SPEC2 - The Gantlet, from Doom 2.
SPEC3 - The Crusher, from Doom 2. It has kinda the correctish tune in it.
SPEC4 - Dead Simple, from Doom 2. Because this level is so simple it hurts.
SPEC5 - Dis, obviously, because there are spiders, and in Dis was our first meeting with one hella huge spider. Also there better be a Spider Mastermind at the end of this level, once them little Arachnotrons are done.
SPEC6 - The Courtyard, from Doom 2.
SPEC7 - The Pit, from Doom 2.
SPEC8 - Cotcha!, from Doom 2.
SPEC9 - The Spirit World, from Doom 2. Kinda similarish theme, and the tune fits too.
BOSS1 - Grosse, from the second Doom 2 secret level. 'Twas kinda similar and stuff.
BOSS2 - Icon of Sin, from the final level in Doom 2. Bosses need to have the same music, especially since the bosses themselves are the same.
Also why's the second boss still spoilered out? Everyone knows what's in there already. I mean it. Everyone. And it's not even too big thing to spoil in the first place.
HEY GUYS IF YOU NUKE CYBERDEMON WHILE INVULNERABLE YOU GET TO FIGHT JOHN CARMACK