You defend your planet, and your enemy defends his. You belong to the red people, and the enemy has all kinds of other colours. Both of you try to damage the other's planet as much as possible. Shoot at your enemy's planet to destroy it little by little. The bigger the planet, the stronger the gravity. Damaged planets on the contrary have a weaker gravity. The closer your missile gets to the enemy's planet, the stronger the attraction will be.
Use the arrow keys to move your little man over his planet. Move the camera with WASD, pause the game with P and reset the battle by pressing R.