I'd recommend Ziggurat. It's a fantasy themed, fps, rogue-lite of sorts. You play as an apprentice wizard making your way through the "Ziggurat", which is a five stage dungeon filled with all manner of traps and monsters. As I said it's a first person shooter but you're using wands, staves, spells, and all manner of magical weapons which makes it feel a bit fresh and distinct. You could compare it to something like Hexen I suppose. There's a lot of unlockable characters, weapons, items, and perks so the replay-ability is there. A full run can take anywhere from an hour to an hour and a half to finish.