In this video guide I will show you how to free yourself from a TNT crate, successfully land all three missiles from a triple missile power-up, and directly hit an opponent with a thrown beaker power-up.
Now for the first achievement, getting the TNT off your head
. Once you hit one in the road all you need to do is spam a jump button. Either hit RB or LB over and over until it comes off and the achievement will pop.
For the next achievement just make sure you get the missile power-up that gives you three missiles
. Just make sure when you fire them that you are behind someone directly or it may miss. Also pay attention to the person you shot at and make sure you see the hit animation of them rolling. That way you know for sure it hit. Once you land the third missile the achievement will pop.
The last achievement requires you to throw a beaker directly at an opponent
. So this means when you get a beaker power-up you hold up on the left stick while pressing the B button. Now you will need to get the distance down when throwing this one. It will have some good forward range so try and get the distance figured out and you will eventually get it. The achievement won't count if you throw it in front of you and they run it over, has to be a direct hit. With several attempts you should get it. Once you hit them with the direct shot the achievement will pop.
On a side not all these weapon achievements can be done with a second controller on local split screen.