Explore and repair a massive alien ship and travel to planets as you try to survive your journey through an unknown universe. Scavenge what you can and try to find a way home, if it's even possible.
This video shows me activating a portal, travelling to a planet, having a look around, and then travelling back. This video was taken from Prototype #3 and so it's a bit out of date now, but the concept of planetary travel is the same.