remember the days of old wad editing where you "WISHED" you could add some cool effect that doom2.exe did not offer. An effect that, if properly implmented, could really increase the enjoyability of a great DM map? That is Crimson.
Stolen music? There is no "music" in Crimson. I did have some fun screwing around with the mp3 format in the alpha versions though... sticking witty intermission music in. The public release will stick with atmosphere, however. I even messed around with the Doom64 and Playstation doom soundtrack... which are now long gone in the current state of the project.
As for stealing, could you tell people to stop putting horrible sound effects into wads with good DM layouts? Example: DW5M1, great map, but it is annoying hearing Jim Carey and the Heretic guy everytime you die as well as the damn Heretic message sound. I am sure that was a blast to hear back in 1995-1996, but it gets old when you have been playing Doom that long online.