Riftwalker

Riftwalker is a rogue-like tower defense in a world consumed by darkness, featuring rich backstory and endless, detailed procedural levels. You play the role of a riftwalker in a scouting party sent to investigate a nearby missing star, but find more than you were expecting - a civilization, or rather, what's left of it. It's your job to find out what happened and make sure the threat never spreads to your world.