The cool part: I added support for procedurally generated levels. So after you clear a level, the slipgate opens and you move onto the next random one... with a new room layout, textures, monster placement, working doors with keys, etc. It's pretty challenging.
I also added Soudncloud integration (configurable in Options) so can listen to the new NIN hotness as you play.
Data files aren't included (id's data is still copyrighted), so the build pulls the freely redistributable shareware pak0.pak.
May it entertain you on your coffee / hydration break(s) today!