Thank you so much for playing! The difficulty was a problem for me because of my lack of knowledge in making bullet hells, and you're one of the only people who like the jam sandwich! (the disappearing is a bug)
To tweak and improve the Jam Sandwich, i'd say have it shooting from the start, and drop jam can can't be destroyed that slows the player down. Probably have only 3 out at a time or something. But the concept for it was great, and added a change to what came before :)