Deathlike2 introduced me to this lost Doom engine action RPG a few years ago, and in the time since it's been
completely reverse engineered and is, as of today, available to buy through Steam:
http://store.steampowered.com/app/317040/Runs in an enhanced engine (first impression, from screenshots, is that the new lighting looks terrible), but with an original mode utilizing Chocolate Strife. Bought in a flash, can't wait to try this out!
Read what you will into "The Original" being used so prominently on that storefront...

The lighting isn't bad at all seeing the game in motion, actually. I kinda like it.