One strategy for Angry Birds Bad Piggies level 21-5 is to fire the Yellow bird nearly horizontal, blasting through the three vertical supports of the leftmost structure. The bird should continue on into the next structure, causing it to fall into the gap. The TNT will detonate and, with a little luck, the stone tower will fall. The score in the video below is 100,040.
If you have a different strategy feel free to leave a comment below; however, don't just post your score via the comments, as that's what the leaderboards are for.

This is a hard one. It requires a lot of luck. My first and only 1 birder only gave me 96k.
I thought it to be a hard score also. But after playing awhile it’s actually pretty easy. The trick, like so many other levels, is repetition.. The video shows the best way, IMO. It’s a one bird level, I don’t think it’s even possible to 3 star with more than 1. So just keep shooting for that I bird score you can live with. Luck and Reps. The highest scores come from getting 2 or more gems at 3k each.. Good luck.
High score for now, just like the video.
This is indeed a 1-Birder, albeit a difficult one to score with though, either everything falls into place as it should, or you’re left biting your tongue.
I agree with you all above. It was a pain and sometimes that house in the middle doesn’t get hit or the stone platform doesn’t collapse. One strategy I did to break past 100k+ was to speed yellow same way as video but ideally you want to break part of the middle house and the right bridge so that the middle and left both collapse into the pit. Yellow bird or debris will then ignite the TNT causing the last house to collapse. That’s the key to a high score though the shot is not easy to pull off.
This is exactly how I got mine. All though on this particular shot part of the first structure didn’t tumble all the way. There’s atleast 3K+ points in that wood. I got two gems but needed more of the first structure’s wood for higher scores.
Frustrating level – had 5 1-Birders, all below 96K, before finally everything fell right for 101030.
I did this totally different. Shot YB almost vertical, accelerating through middle horizontal block, activate TNT sending stones into right structure which fell leftwarr over second and first structure.
Yellow bird through the right structure, hits the permanent base of the middle structure where it frees the bridge, then drops down and blows up the TNT. The rest was a chaotic mess of flying debris and collapsing structures. It was nothing like the video, but I got a 3-star score and after hours just trying to 3-star this level, I’m moving on.
I forgot to mention how important luck is in getting a 3-star score. Other than getting the first shot started right, this is all luck.
I agree, had a nightmare over this level. Requires more luck than skill. Tried pretty much everything. Once lucky and 99850(still below average). Never going to play this one again.
Unstable level.First house self-collapsed.No help whatsoever
@mvnla2, unstable level
After reading the comment, I came to 103410. the video was very helpful
Had about 20 goes at it just the same as the video. The order of collapse was the second structure falling to the left onto the first. Very reluctantly the first toppled left as well. Both pigs gone. In the meantime the yellow bird rolled onto the TNT and the right hand side collapsed taking a few crystals. I wanted to take a photo but didn’t dare!