Scoring
The higher the point total on a level, the more stars you are awarded. Points are awarded for destroying the target pigs and their surrounding structures. You also get points for each bird that is left over when all the pigs have been eliminated, so it is important to get the most out of each bird.
Structural Weaknesses
Shooting the birds into horizontal beams often forces a structure to topple over sideways. This may cause increased destruction and a higher score. Similarly, destroying the bottom level of a multi-tiered structure can cause the entire configuration to crash, taking targets out along the way.
Velocity and Angles
Generally, the harder a bird is propelled into a structure, the more damage will result. However, sometimes a well-placed finesse shot can cause a domino effect, and actually result in more damage. In addition, changing the angle that the bird strikes can cause major changes in the amount of damage.
The Birds
Small Red Bird: This basic bird does not have any special abilities, and is average at breaking through the wood, glass, or stone.
Blue Bird: A screen-click during flight makes this bird multiply from one to three. The blue bird destroys glass better than wood or stone.
Yellow Bird: The yellow bird̵7;s specialty is speed. A screen-click causes it to zoom through the air with greater velocity and decreased arch. It excels at breaking through wood.
Black Bird: The black bird resembles a bomb. Fittingly, a screen-click prior to impact will cause it to explode. Without a screen-click, the black bird will explode shortly after impact. Additionally, the black bird crashes through structures with the most force, and therefore causes more damage.
White Bird: A screen-click causes this bird to lay an explosive egg during flight. However, unlike the other birds, once the player deploys the white bird̵7;s special skill with a mouse click, the white bird shoots up and out of the screen. If you do not deploy the explosive egg, the white bird still acts like a red bird.
Green Bird: A screen-click makes this bird act like a boomerang. The bird̵7;s speed increases after it makes its turn. It is useful for hitting hard-to-reach places in the back of a structure, or if initially aimed away from the structure, it will turn back toward the structure and cause more damage because of its speed.
Big Red Bird: This bird breaks through objects with the ease of the black bird, but does not explode.