Congrats on your submission! I had a lot of trouble getting my mind to understand that shift was space. I paid for 3 ammo upgrades, got the first 2 enemy spawners but couldn't get to the 3rd one. I wasn't sure if I could just jump past the enemies or if I needed to stop them from getting past me, so I wasted my ammo trying to stop them. There was an option to buy grenades but I didn't know how to throw them. After dying and retrying a couple of times, the music stopped playing. I'm not sure what engine you used, I used Godot, in Godot you have to double click on the music file and enable loop, otherwise it only plays through one time and stops.