Really nice, thanks for sharing :) works as advertised ;)
Ok, so now the mocking :P
I added the following code at the very start, just to prevent me from accidentally closing the game right after starting it (loading takes a while and I was too impatient):
textSize(100)
printAt(7, 3, "loading...")
update()
EDIT: After playing it a little more, I can still say it is a really nice game! I feel like you know best what you want to improve, so I think I'm telling nothing new if I say I hoped to fire my last bullet to get more bullets, but it directly ended the game in stead :)