The opening in the first one had a lot of potential, but the decap was kind of anti-climactic. The next two seemed to be more random than intentional, as in, "Oh hey, that happened, and it looked cool, so imma save it". The last one is really the only one that stands out a bit, but even then, it's kind of stiff.
My advice? Try playing with some relaxed joints, as they really "fluid out" your movements, and learn to spot opportunities before they randomly happen, so it won't look as... Well, random.
As mentioned earlier, the first one had a good start, so try to work more on the stuff that happens after the start, and make the "phases" flow together for more momentum and OOMPH.
Oh, and use more joints at a time.