I really enjoyed the music. It has such a chill vibe. I used a similar type of track as background while working on our own jam game, so this one put me in a good mood right away. The core idea is fun and the controls are easy to understand.
After two waves the game seems to stop and nothing else spawns for me. It would be cool if the waves kept coming and slowly became faster. Maybe from time to time you could give the player a small power up that lets them shoot two or three bullets at once.
I also noticed a small red cross on the screen that looks like a debug marker or some leftover UI. Right now there is no clear goal or ending, only a clear start. With some kind of score target or endless mode this could become a really nice little arcade game.