Techtonica is a first-person factory building game set beneath the surface of an alien planet. Work alone or in co-op to build factories, gather resources, research new technologies, mold the destructible terrain, establish a base of operations, and uncover long-forgotten secrets.
https://www.youtube.com/watch?v=9FK15vuZ9yc
https://www.youtube.com/watch?v=rdlT-VrH-ZY
https://www.youtube.com/watch?v=EFZL7IGAg0o