Comment by walrus01

I think the big difference for me, after playing a lot of Wolfenstein 3D, was two things... The system I had it on didn't have the CPU to run wolf3d in something like a full screen size, it was something like a 386SX/20. By the time DOOM came around I had a much more capable desktop. Secondly, wolfenstein 3d was everything on a flat two dimensional plane of grey floor. There was one size of wall or door tile and everything had the same ceiling height and same wall height.

DOOM having stairs and up/down movement, and vertical elements to the level design was really revolutionary at the time.