Good implementation of the theme, but the movement is soooooo slow...
I managed to learn what the yellow balls do (well implemented in game tutorial) but I never learned what the other balls do. I went up the long chasm to the top, but there was nothing there to do and no way out (except back maybe?).
AS for the controls, I think it would have been better to have both connecting and disconnecting on the same button. You know whether a ball is connected or not, so upon LMB you can either connect it if it is not connected or vice versa. I was struggling with the simple control scheme, especially because in my mind LMB to connect and RMB to disconnect would be more logical, but having one button would be even easier I think.