Evil aircrafts are attacking you and your brothers. Now it's about to defend yourself.
In order to get the whole thing a bit more interesting, you can upgrade your people and rockets (e.g. stronger/faster rockets)
Left mouse button = left turret
Right mouse button = right turret
Important note: In order to be successful, it's necessary to target aircrafts, until the crosshair turns red (about 1 sec.)This time may be reduced when you buy an aim upgrade (rightmost).