The two stone blocks at the left of the bridge is the key (althrough you can shoot the Yellow Bird up to the thin wooden block and pop the helmet pig without kicking those stone blocks like the video, but it gives lower score). Shoot the first Yellow Bird to the two stone blocks and kick them off the bridge. Then, shoot the second Yellow Bird into the bridge and pop the left helmet pig (whatever you can't pop him, that's OK). Now, shoot the White Bird and drop an egg bomb to the place that the helmet pig was standing. Then, shoot the second White Bird and drop the egg bomb at the left pig at the bottom of the bridge, sitting next to Moustache Pig. Then, shoot the Yellow Bird to the Moustache Pig and use his speed to finish the level. If the level is not finished yet, shoot the first Boomerang Bird to pop the remaining pigs.