Support Avorion and back it on Kickstarter: https://www.kickstarter.com/projects/1051106571/avorion
Avorion is a sci-fi space sandbox where ships are generated and built out of blocks and that allows players to follow their personal playstyle in either single player or co-op multiplayer. And yes, that includes blowing up your friends!
Avorion focuses more on space combat and actually flying around in your ships instead of solely on building. In order to secure the funding of the development until the Steam Early Access release, a kickstarter was launched.
There's also a free demo available for download: https://www.avorion.net/demo/