Really cool mechanic with the tiny planet. Its makes just basic projectiles being shot at you way more interesting with them wrapping around.
The boss fight felt good. One complaint might be hitting the boss wasn't that pronounced.
The charge mechanic was neat but I feel either getting it recharged once the boss fight starts or maybe getting one recharge after killing enough enemies would have been nice. After I used them up I quickly forgot about the mechanic, and they didn't feel that game changing when I did use them to justify such a scarcity.
Overall, very cool concept, enjoyable execution, good entry.