Fly through an infinite universe, and perhaps make a few stops along the way. Use left click to fire your thruster and your mouse to steer to try and protect whichever planet you decide by pushing other ones away. Hovering your mouse over a planet brings up a menu – hit the check button to make it yours!
Low on health? Give your planet a nudge. Move it fast enough and it’ll start regenerating health and release a glowing trail which you can fly through to use to charge your gravity gun! When your ship is flashing yellow, simply right click to release a beam that pushes away every planet that isn’t yours.
How far can you and your planet travel? How much time can you make it last?
And remember, if protecting gets too stressful, there’s nothing that keeps you from simply wandering.