Enjoyed playing this one and had a top score of 15 which I was pretty happy with. Could have got higher with smaller kicks but where's the fun in that :) might be a good idea to have a height limit that stops it counting if it is a really small movement so that the player does have to kick it over a certain height. Also a arrow on the top of the screen that moves depending on where the ball is coming down would help anticipate the ball a bit better.
Liked that you could play in a team also and might be nice if it bounced off the side of the walls so that it never actually went out and you could do some big hits across the screen to the other players.
The player position and movement was also great and kept me playing trying to beat my top score.