900 Deep in the Dead is a takeoff from the popular 100 Lines project, the latter began by Adam Windsor. The concept - make a map with only 100 lines. The challenge is in creating something that both looks okay and is also entertaining. Doomworld Forum superstar Jay "Jayextee" Trent took the idea and ran with it for a full episode replacement for Doom's Knee Deep in the Dead. Trent tackles the constraints in what I'm assuming are staples of working within 100 lines, using abstract geometry, double-sided linedefs separated by height to reuse walls, and other bits of level geometry for monster closets.
