NOTE: NO codes at all work at the "Nightmare" level save for IDCLEV.
NOTE: The codes for Doom II are identical to those of Doom except for the clipping code which was changed to IDCLIP and for one new code: IDMUS## (where ## is from 00-35). This code will let you cycle through all of the music in the game whenever you want. Cool!
A big thanks to Ben Farrell for his help on this section. Thanks man!