Dodge the asteroids or shoot them down to gain bonus points. Use the mouse to direct the rocket. Press space to fire the laser (but be careful, it takes a few seconds to reload, and takes longer if you miss). Don't get hit (and watch out for a nasty surprise)!
The basic idea is from Usborne's "Coding for beginners", but the rest is by me. I will hopefully update this in the future and add some power-ups, please leave some ideas in the chat!