The idea of the game is really great! I love how you took time to animate the fly's wings to flutter, and you've added sound effects to everything!!
Some things to keep in mind:
1. I wish the bgm doesn't start again from the beginning when I go to the next level. It brings a pause to the game, and I wish that didn't happen b/c im so into playing it.
2. Like how you show score at the end, but im guessing the score will be the same every game if you win. Maybe can also display how long it took for the player to finish, then it's more incentive to keep on trying to beat my time.
Good job :)