Z.A.R. (Steam key/Region free).

http://store.steampowered.com/app/351820/
In 2097, the mining of minerals and other natural resources is completely automated and controlled by supercomputers. The planets that are mined for ´Iberium´, an essential mineral to control pollution on Earth, are called Z.A.R.; Zones for Artificial Resources. The ´central computer´ that controls all of the mining robots is hit by a meteorite and enters a frenzy. It starts building robots with weapons, intent on conquering more planets. A single soldier, Colonel Hermit, is sent to deal with this threat.

Explore vast, open, low-gravity terrains whilst gunning down hordes of enemies.
Enjoy the CD-quality audio soundtrack.
Destroy your enemies with a variety of weaponry.