Here is our Mighty Eagle Total Destruction video walkthrough for Angry Birds Bad Piggies level 21-12. (If you’re looking for the 3-star walkthrough video, click here.)
Fire Big Brother into the bottom of the leftmost tower. Bomb the rubble with the White bird, then launch the sardine can head-on into the second-to-last tower. The can should fall towards the base, allowing Mighty to destroy nearly everything. If you have an alternate strategy please feel free to leave a detailed comment below.
1. Big Brother into the left most tower and have it fall to the ground.
2. Activate and launch the Sardine Can immediately after BB’s launch and have the ME hit BB on the ground and ME will bounce into the structure.