This game is amazing, I didn't even know it was for a game jam while I was playing it, and I still thought it was great.
I love how the different upgrades increase replayability.
and the music and art are very nice, and the color changes are super cool.
My only complaints would be that the second boss's music seems slightly cluttery while in-game, and some of the third boss's attacks feel kinda cheap.
overall, if you turned this into a full game and sold it for $15, I would totally buy it!