Very nicely done.
I agree the explosion at the end could have been done better. With all that smoke there had to be something producing it that would cause a volumetric explosion, not just debri.
The smoke coming out the back isn't always aligned to the exhausty thing, looks like it can't keep up to the animation.
Also, the particle size should get bigger towards the end of the smoke's life. It will get rid of that small round blotty effect as it dies off. Also when he slams into the ground, and the smoke goes up, you can see that the particles are square. kind of odd
How did you do the smoke?