Avorian (demo is free on their site)- I have not played a lot of this yet, but it looks fun, has decent controls and some serious depth to the game as a whole.
Empyrion Galactic Survival- Just plain one of the best games out there right now. The dev's are extremely active and actually give a crap about their game. It is an alpha, expect bugs, patches, wipes and some more bugs. But this game will have you hooked. I have played over 100 hours in just the past month or so. Make sure you have a more modern pc though. Voxel based games need some horse power to run right.
Space Engineers- One of the best building/space games out there, period. There is not much in terms of npc's to fight though. A few here and there.. But the building mechanics, automation and mechanism creation is just awesome. Plus, they just recently went Beta on this game. There is even a mini campaign/tutorial to teach you the basics.
Star Citizen- I have not played it yet, but a couple of my buddies have this and showed me this map, the actual map of what you can currently play ingame: https://robertsspaceindustries.com/starmap I don't know about ya'll, but this sure looks like a lot more than just some testing systems. It is really starting to look like it's ready. If I had the money I'd probably go ahead and get this.
Political correctness is the politically correct version of saying: Shut up Slave