Planet Defense

Asteroids
Prevent them from destroying your planet by fireing missiles close enough for the detonation to kill them. Asteroids split into smaller asteroids when hit. You can place your detonations with precision to kill several asteroids at a time, and even the parts which they split into.

Life
The game ends when all life on your planet has been extinguished. Life continously regenerates though as time passes so it is possible to recover even from the brink of destruction.

Missiles
You fire missiles by aiming on the screen and clicking the left mouse button, the missile will detonate at its target location after a short time. Missiles contiously regenerate but at a relatively slow rate so you have to make each count.

Chains
When your detonation hits an asteroid an additional explosion occurs which can propagate to other asteroids to create what is known as a chain. The longer your chain the more score bonus you will get.

Gravity Wave
The gravity wave is a secondary weapon you can use against the asteroids, you fire it by double clicking the right mouse button. The wave will apply force to all asteroids sending them away from your planet for a short while. It will also destroy all small asteroids instantly. The gravity wave costs 10% of your total score to use and after each use has a cooldown before it can be used again. The cooldown increases with each use.