Thank you very much for your feedback :D
I have to say that I usually participate in the Trijam, so I'm used to doing games in 3 hours (or almost^^). So if I'm given a month to create, I've got time to have fun xD
Yes, the screen is sometimes very overloaded with projectiles. For many of them (like cards or magic hat stars), succeeding in making the boss vulnerable makes these projectiles innocuous. But for the last bosses, it's actually quite complicated. After the jam, I'll try to balance things out a bit :D
Anyway, thank you very much for your compliments ❤