I think we should use something else to get rid of the gestures and all this stuff once and for all.
Level:startLevel starts the gestures and the music, maybe we should do a Level:stopLevel that stops what start did. This method will be basically the first lines of Level:destroy, and destroy will call this stopLevel method.

And finally, you call level:stopLevel when the game ends. The level stops playing, but the cute animals stay there but we can't interact with them (it may require a little more code to do that).