A lot of times, your movements seem pretty static in a sense that the figures stop drop dead after the end of each movement. This is becuase the movements don't flow well; there is no transition what so ever between one movement and another. What you need to think of, at this point is to learn about the principles of animation, and especially
follow-through and overlapping motion. Other than that, your combo's choreography is off; the idea of choreography in fighting is to keep the viewer interested as long as possible. It's not always an easy task, but at least in your animation you can make the punches flow together. Don't make the second punch wait for that long. And in order to make the animation as a whole is convincing you'll need to work on your posture, which is a general flaw amongst most animators here—even I suffer from it sometimes, so don't feel too bad about it. If you read
this tutorial, you'll probably get what is mean by line of action which is what clarifies and exaggerates a pose in order to make it look and feel more convincing than it would normally be irl. Key in animation is to convince, not to imitate reality. Next is your background, if you want to compensate for bad movements (bad idea), then at least make a BG that is pleasing to the eye, and it doesn't not require a great deal of aristic skill to do so. Even something as modest as this can suffice.
It might be worth to note that this was al mouse—I do have a graphics tablet, and I prefered not to use it.
If anything the tremors sort of helped with adding power, thought you over did it.
Hope this helped. Keep it up.