Ok, first off. M to mute, N to unmute. P to pause, U to unpause. Its written all over the game. NO COMPLAINING ABOUT THAT.
Holding the mouse down is auto-fore. F toggles on and off. the freeze shot(if you have the powerup).
Don’t forget to buy crap at the skills shop after every level. You’ll die without the skills.
Fight through 10 levels of alien invasion while upgrading your cannon after each level. Enemies start gaining abilities at Level 3.