There are two different controls: Mouse, where you use the mouse to move the ship, and click to fire. There is also keyboard, where you use the arrow keys to move and fire. I recommend using keyboard, as the mouse is a bit glitchy.
Huge thanks to @TheSquidNextDoor for many of the sprites. Wouldn't have looked so good without them. Many thanks to the people who helped in the forums for some scripts that I could not think of how to make.