WASD for movement, click or space to shoot, mouse pointer for aiming, p to pause, z and x are upgrades (z is power, x is shooting speed) You can also click on the respective buttons near the top right. Money/score is displayed on the top left, 5 for the first purchase of an upgrade and an additional 5 for each one after. There is a secret in the pause menu, see if you can find it.
This was a 45-minute game challenge, I hope that people like it. The thumbnail was made after the 45 min time though.
