Here is our Angry Birds Birdday Party (Birthday Party) walkthrough video that will help you unlock the Secret Cake Achievement found level 18-15. If you have a different method for obtaining this that you think is easier feel free to leave a comment below explaining your strategy. The steps for obtaining the secret cake achievement are as follows:
- Use the Yellow Bird or the Orange Bird to hit the TNT and destroy the donut on the far right hand side. You need to leave some debris above the TNT that is adjacent to the piece of cake. When you complete the other steps this debris will hopefully fall down and blow up the TNT.
- Destroy the treasure chest that appears BEHIND the slingshot platform with White Bird.
- If no debris falls through and you have an opening, you can still try to fling the Boomerang Bird into the gap to hit the TNT and get the cake! This won’t be an easy shot.