One strategy for Angry Birds Bad Piggies level 21-10 is to fling the Red bird straight ahead into the inverted cart. The bird should bounce back and pop the leftmost pig, while the cart and tower will detonate the TNT to the right. The engine will also be pulled by the falling cart, bringing the pig plummeting to the ground. The score in the video below is 103,290.
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.

2 birder 3* very possible-first bird as video, 2nd bird (if needed) high to land and touch wooden tip of platform, slight delay and whole thing should topple down. 97,610
Don’t be in too big of a hurry. There was no sign top structure would fall, but I waited about 10 seconds, and then the whole thing came down.
On another try it took a full thirty seconds for the top structure to fall. I would say that as long as there is still sway, there is a chance of collapse.
Wow, I went to read the comments since I could never get the bounce up to pull the top tower down…..and as I was reading it came down on its own. Super!
This one should be called the Sway & Wait level, and even then, it doesn’t always fall as it should. I need to return to this one and raise the lousy score I got.
The name of this level should be WAIT. The tower will fall sometimes after a minute of waiting. Patience ….
Patience from the ABN bunch? That’s just asking an awful lot.
I know right! Another level requiring patience, lol ;-)
I noticed a few extra points can be calculated from the wrench tapping up and down on surrounding “debris”. I’ve also gotten the gas can to topple over but it never breaks and I haven’t noticed if any real points came from it? In this level, every bit helps!
Excellent level. Had real fun playing this one AMslimfordy’s video helped a lot. But instead of straight ahead I shot Red in a high arc. Eitherway, it worked as a 1-birder.
@Kimmiecv this is an easy one…like everyone else i hit the middle structure just on the edge, Lil’red bounced into glass structure..the middle continued forward causing the string with the motor to swing..then just wait til the top falls:)
Yeay something to look forward to @Kathy! After I finish the evil level I’m going to need it!! :/
I skip the red bird on the ice and often get better destruction than just hitting the middle structure – the rest is pure luck, hope the cart flips and stays just below the overhanging structure, eventually toppling.
Thanks for the pointer @cresteddirdir
This level really requires a lot of patience and time.
I had the wrench quivering around on its own for a good 2-3 minutes at one point. Kinda creepy…