Very impressive for a game jam, I like the way you can dig into the planets, but I just wish this mechanic impacted more the gameplay (like, maybe destroying the planets once they're completely depleted ? Or dig tunnels through them to navigate faster ?)
The gravitational effect is really enjoyable by itself, although it gets a bit weird when the character suddenly rotates to match the surface it's landing on. For a low poly game it's really beautiful, and has a lot of potential. Don't let that idea go, I think you can do something really impressive with it. Nice job :)