Wonder what that device uses inside? I certainly doubt that it is a shrunken down Amiga chipset. Possibly an Atari ST clone though, that was fairly basic.
Otherwise, maybe they are just C64 versions of the game inside a modified C64 game joystick (possibly running faster than the other one).
It would be nice if Speedball 2 was available as well.
I wonder when you'll be able to get a Megadrive inside a joypad :p