This is a shockingly good game (pun intended)
The idea of the game and the use of two themes at the same time is great. Shooting and movement feels very responsive and the sound design is well made!
Only thing I noticed is that I would sometimes die (I'm guessing I touched an enemy) and wouldn't get proper feedback for it. Also, I would sometimes lose when time ran out, even tho I already reached the goal. (The level still unlocked, guessing this is a fairly easy fix)
Besides that, really good job!