Very nice game! But there are a couple of problems:
1. Spawn on kill upgrade seems overpowered. It fills the whole screen with shapes. I suggest capping it at 50%.
2. In lategame, the beams start consuming absurd amounts of energy. The power increase becomes too expensive, so the rounds end in 10 seconds. Would be nice to have an upgrade that would decrease the power consumption.
3. The stars felt incredibly rare. Even at max spawn chance, they would spawn about 1 round out of 3. And the concurrent stars upgrade felt absolutely useless.
4. Why does pierce upgrade have 80 levels?