Paranautical Activity combines the classic FPS action of games like Doom and Quake, with the randomness and difficulty of modern roguelikes like Binding of Isaac and Spelunky. I don't usually shout out sales since our sales page on GOL, but these guys really need it, hope Phoronix readers don't mind me linking to GOL this time as it's a worthy cause.

http://www.gamingonlinux.com/article...reenlight.2075