Very nice. :)
My only problem was that there were unnecessary pauses between 2-second action bursts.
There was a 2- second action blip, then a 1 second pause. 1/3 of the time, they were standing looking at each other.
Also, I feel that during the running scene, you showed their legs too much.
I'm unsure as to whether showing their legs (after their eyes and just before their clash) added that much to the suspense, and you showed too much of them.
Also, some of the moves (a strict minority) were unnecessarily showy or unnatural.
I wrote a lot, yeah, but that tends to happen when you're nitpicking. ;)
Very, very good animation. 5 stars. :D