I love bullet hell games and shmups, and this one is great. Good job on cramming it all in 64x64. The movement is precise and the shooting is satisfying. I also enjoy the quite unique approach of despawning the bullets when the enemy that fired them is eliminated. Encourages a more offensive gameplay.
I did run into a bug. After restarting from the game over the enemies were still spawned. I took them out but then no more enemies spawned.