Bad Piggies 21-1 is the three hundred first level of Angry Birds (if you don't count the bonus levels) and is also the first level of the Bad Piggies episode.
Strategy
First, split a Blue bird into the leftmost TNT, spraying the level with debris. Bomb the middle of the level with White bird. It should ricochet into the hill on the right then roll down and detonate both TNT below. Those crystals are worth 3000 points. Finally, launch yellow aiming at the last TNT on the right, causing the boulder to fall on the last pig.