Earth is under attack! Asteroids are falling from orbit and it's up to you to stop them. Remotely pilot a set of shield platforms to smash them before they go kaboom!
The space aliens are relentless, once an attack starts it keeps getting stronger and stronger. They won't give up so you can't either. Beat a wave and get a shield replacement or a bonus if you're at full strength. Get consecutive bonuses for bonus multipliers.
Too easy? Try 'joystick mode' for a harder challenge.