Try NetHack. infinite hours of replayability (the whole game is algorithmically generated and every time you die, every item/tool/weapon/map has a different nam

Try NetHack. infinite hours of replayability (the whole game is algorithmically generated and every time you die, every item/tool/weapon/map has a different name and effect) and it's FOSS ;-) Also it's a pretty hard game on its own. If you're a fan of challenge i'd suggest you try it.