Hot answers tagged insanely-twisted-planet
Those act as checkpoints. Each time you fly into one, your health (which is shown by wear and tear on your ship) will be refilled, and your current progress will be saved. It will also act as a protective barrier, should enemies try to attack you while you're inside. Enemies who deal damage by flying directly into you will be disintegrated.
I don't believe there's any way to return to the home world. I think videos and concept art carry over if you start a new game, though I don't think the actual collectibles do.
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