This was a wonderful little action-puzzler! You nailed the core gameplay loop, and I think you scaled the challenge rather well. I'd love to see more levels beyond the wide-open arena; I think you could make some really interesting challenges.
The biggest thing I missed from this game was sound -- perhaps you did implement audio, in which case my machine just didn't run it. But in any case, you could really underscore the rhythm of battle if you introduced some juicy audio cues for the charge, movement, and attacks.
Over all, though, you made a wonderful game! I'd love to play it again after you've had even more time to make it shine!