Really cool idea!
I wished that the treasure stayed on screen a little longer, and that the player blinked when hit. Sometimes it was confusing to know what side of the ship each button shot from, but that was part of the fun. The music fit the theme, but it wasn't very creative. Innovating or riffing on the song may have helped it to not feel so repetitive.
Really solid work! I didn't make it to the boss, but kinda want to try again. The art looks great given the limitations! Awesome first jam! Keep it up!