Wow, you can animate almost perfect proportions and you are animating them really well. You can clearly see that you concetrated yourself more on the feets, because they were damn well animated. Doesn't mean, that the upperbody was bad. The punch looked a little rushed, you should've added one more frame between it, imo. I would've loved to see some finger movements on the other hand in the back and it would look a little better if it didn't stop that suddenly.
Still amazing job! I look forward to your stuff. What dimensions did you use?