Launch your bird at the angle shown. The angle does not have to be exact for this stage as long as you can get a good angled shot to break the wood and snow pieces holding the laser shooting head.
The key to get the three star mastery rating with this stage is to rely on luck and enemy lasers.
Power Activation Point
Activate the laser powers whenever you can get a clear straight shot at the leg base.
First Shot Result
Your laser gun breaks the balance of the enemy laser head. The enemy falls and continue to shoot out lasers. The enemy lasers destroy all the pigs and plenty of blocks, netting you with the three star mastery rating.