The first animation: right after the red guy grabs the black guy, you tried to ease a little, which is a good thing, but it was wobbly. Also, the kick was a tad bit unnatural, especially when he starts to fall when the red guy grabs his leg, because nobody falls that slowly and awkwardly lol. Overall pretty cool animation, just work on what I said :)
The second animation: Work on your reactions. The grey guy was animated pretty well, although that kick was a little hard to see. But when the first guy was hit, he well into a very awkward pose and then just stood there. Finish out the reaction, don't just half ass it. The second guy looked more tweened then actually fbf animated. As for the third guy, I know its supposed to be funny but it would be better next time if you actually animated him haha. Overall pretty good, better than the first.
The third animation: I really like the way you animated that muffin man getting ready to fight hahaha XD Finish that one it's looking good.