I made a bit of mistake, amd ported the same game to web...
About the game: I think the concept is good, but feels too forgiving: as the shake mechanic is unlimited, and not piling up at all.
It can be balanced, by making each Shake drop extra 3-6 Balls to the playground.
It was fun to play, and made me think to make a new game again! (+watching someone remaking Contra's first level in 3D, was also motivating)