Shoot the first Yellow Bird next to the Small Pig that stands next to the TNT at the top. The TNT should fall and clear the left side of the structure, only remain some pigs at the right side with some luck. Shoot the second Yellow Bird to the remaining pigs to clear the level. Or you can work your way from left to right and it will be easier for you. This and the remaining birds will reward a total of 117k+ or you can get a higher score if you have lots of luck.