Day 1:
-Blur and shakycam isn't the way to go.
-Going a bit too fast to really figure out what move is being done. For example, early on the second punch is pretty much lost in the noise.
-Keep track of which side the character is facing. I saw you accidentally flip the character's orientation a couple of times. For instance, after the punch and before the sweeping side kick.
-Anticipation is your friend. Remember that your viewers have to keep track of what is happening. While it may be tempting to make everything superfast and all that, you end up doing a lot of things that your viewers just can't pick up on or see. This ultimately makes the effort you put in wasted, and the animation overall worse.
-The wobbles in the feet and limbs are pretty intense. I'd suggest you mitigate this a bit, (Just a LITTLE bit), by doing simple things like doubleframing just the feet or whatever body part is moving a very short distance. In your case if you double-framed the feet for just an extra frame or two it would look much better.
Day 2:
-Still abusing that shakycam. They are things that can add to an animation but overusing them really just lessens the effect. Save the shakycam for the *really* heavy blows if you must use it.
-The second punch doesn't match his movement prior. It was anticipated incorrectly.
-After the fourth hit, the stick figure flies WAY high into the air and sort of slams down into the ground way too quickly. I understand that you wanted to keep the flow of your combo going, but this is not the way to accomplish that! You don't want to break any rules in a way that it becomes apparent to the viewer. In my case I was able to catch a frame of that guy being launched way high into the air.
-Same issue with the feet. Unless that's what you're going for, it looks too messy for my tastes, but hey.
-Generally, anticipation man! You need more of it. It'd help slow down the pace of the combat while simultaneously increasing the weight of the attacks in a way that shakycam couldn't, AND make it easier to follow!
All-in-all though, I actually enjoyed watching those. You have a pretty nice sort of flow where everything is always moving, which is a very good thing, and as far as animation issues go, it isn't the worst place to be. I can look at those and definitely say that the characters feel as if they're alive.
Just slow down and make sure we can actually process what's happening, yknow?