Very cool premise, which solves a problem of old shmups where there's a fire button but you never have any reason to let it go.
Two things I would've liked to see are being able to start on later loops instead of having to start over from loop 1, and more mutation on the enemy copy, so that it can require more strategies than just being economical with your shots.
Art and sound design are wonderful, I thought the player was a puppy instead of a bunny at first.