Orbital speed is really bad for a few levels (as it means that you move just fast enough to not kill enemies, but slow enough that they can catch you), but then becomes overpowered and can ignore enemies!
The accuracy upgrade reappears every time you change scenes (so if you die, or if you go to the next moon)
The 'main screen' always shows 5/5 moons remaining, although it does track the moons properly
You call take_damage on a whole bunch of areas that don't have that method (PlutoArea2D, CharonArea2D, MeleeRangeArea, StyxArea2D, etc), leading to *massive* logspam
There's a minor memory leak in the ObjectDB (I didn't run it with --verbose so don't have the full story there)
And I feel the game petered off after the second moon, and it was just about waiting, then manually aiming as the 'orbital aim' doesn't work for very large distances.
All in all, I rather enjoyed this, and hope you give it some post-jam updates and such!