The concepts and ideas are there. I especially liked the each color has a different bullet type. Doesn't seem balanced though as I can easily get swarmed.
Viewing post in ARITHME-TECH jam comments
Could you elaborate on why you feel you're easily swarmed? The game is intended to be challenging, in part to ensure it does not drag on for too long. Because of this, it should be fairly normal for there to be several enemies on screen at once, requiring you to quicky change targets. It is worth noting that while the arena is green it doubles the amount of targets that spawn for the duration.
If it's happening while the arena is blue it could be bad RNG or skill related, one thing that may help is holding down LMB to continuously fire, which I'll have to add to the description.
I may in the future make it so the difficulty at the start is lower but ramps up, but I had wanted to keep game sessions on the shorter side.