Planet Defense - strategy game

Planet Defense is a free online flash game of the category strategy games.

In this game you need to protect helpless Earth from giant asteroids and devastating comets using automatic turrets. The gameplay of this game is simple. You've got to purchase turrets and drop them on the orbit, aiming at the advancing space bodies. If you destroy an asteroid or comet then you earn some money to buy more powerful defensive weapons. If Earth is destroyed then your game is over.

Mouse.
Use cursor keys for moving on map.
1-5 keys to quick place defence ships (don't work in fullscreen mode).

A context menu should be shown when right-clicking or, on touch devices, long-pressing in the game. This menu especially allows to play in full screen and control the volume.