The instrument on the descending tones that repeat every two bars throughout the song is changed for the sixth 'repeat' of the song in D_DDTBLU (to a kalimba), and is not for D_DDTBL2 and D_DDTB元 (where it remains the instrument from the fifth repeat - FX 2 (soundtrack)).The intro passage is an extra measure long in D_DDTBL2 and D_DDTB元.

A cymbal crash can be heard at the very beginning of D_DDTBL2 and D_DDTB元, which is absent from D_DDTBLU.Taylor Blues', which is present thrice in the IWAD, exists in two slightly different versions: ↑ Information has been derived from the 2023 Doom source code leak, which contains original source MIDI files for Doom 1 and Doom 2 that are otherwise not found in the OS/2 version.↑ 1.0 1.1 1.2 1.3 The inspirations for the tracks noted above are substantiated by metadata comments found in the unreleased MIDI tracks released by John Romero, many of which are alternate versions of the MIDI tracks used in Doom.

Wolfenstein 3D - Ultimate Conquest (E3M9/E6M9 music) Spear of Destiny - Evil Incarnate (MAP21 music) Wolfenstein 3D - Zero Hour (E3M4/E3M8/E6M4/E6M8 music)