The game was fun ! Getting the upgrades was really enjoyable I could see the progression.
However I think it would have been better if I could fire multiple bullets, because when a bullet is bouncing over the walls I could not shoot anymore and I ran into a bug where the bullet had too much speed and escape the scene sooo I was doomed to death since I could not fire anymore.
Other than that, good job ! with the sfx the music and the screenshake it has some juice !