Another one that is very popular at the moment is 'FTL: Faster Than Light' . Set in space. Very basic, very lightweight indie game that I have really enjoyed. Not enough space here to do a full review but check out totalbiscuit's review on YouTube if you want a look at it. Costs about $5 for a DRM free edition or a steam key from ftlgame.com. I'm not affiliated at all just a happy gamer.