I made it on a sick day when feeling delirious, and added bits and pieces over the next few eves. It was going to be a dungeon explorer but it just turned into a mash-up of games I had in the '90s; Wolfenstein 3-D, Dangerous Dave in the Haunted Mansion, Nightmare 3-D, Ken's Labyrinth.

http://antongerdelan.net/games/dungeo/ alt link (if scrolling page is annoying)
src: https://github.com/capnramses/mansion