Very nice and pretty fun! The action is rather fast-paced, and the bullet-hell aspect is really well done!
The only 2 problems I found are that 1. the base movement speed is so slow that 3-4 sneaker upgrades are basically a necessity; 2. Enemy can spawn ON you, and their types seem completely random from the available pool. I've had waves 1-2 harder than 8-9 spawn.
Overall, very good work, has a lot of potential!
(Sorry to hear you got ill, I hope you're better now!)