Alright, it’s not a true roguelike in that it’s not turn based and you can continue after death if you want, but there’s no need to split hairs. Transcendence is really fun. And it’s free.
I might describe it as “Diablo in space”. You’ve got a randomly generated “Dungeon”, where it’s a series of solar systems connected by star gates. You pick one of three ship classes, and you fly around, kill stuff, collect the loot, and upgrade your ship. There’s even a bit of a storyline and a pretty well fleshed out universe.
The graphics might be considered a little simple, but if you can get over that there’s a really compelling game underneath. Something that’s well worth the zero dollars you have to pay for it. I highly recommend it.