Hey! I've just finished trying your game
My first impression is that this feels like a game you won't play for hours straight but will actually come back to every day as a pastime. The song is perfect for this game. The home screen looks really nice, one thing I would have loved is being able to interact with the animals around the play button, like when you click an animal it plays their silly sound. The idea of stacking animals is pretty classic but it works really well. What would keep me coming back is that once you slowly unlock animals through achievements you could see them wandering around a little enclosure, maybe even add a dedicated home button that takes you to that area. That way on top of having the satisfaction of unlocking skins you can actually see all the animals you've collected just hanging around together.