Surprisingly well-balanced
Usually most Flash fighters, even when developed with a great deal of skill, end up imbalanced because the creator has a single vision of how each character "should" be played. This game, in addition to looking and sounding great, is very balanced. Juggles are powerful, but they are powerful universally. I started out playing on the highest difficulty and didn't have too many problems.
My only real gripe is the last Convict level, which, at least on the highest difficulty, is simply a matter of luck. Since the parry/guard system is not sufficiently equipped to deal with multiple opponents attacking simultaneously, you quite literally cannot move and are relgated to air parries and power-ups.