This game was really fun to play ! Reminded me a lot of Geometry Dash on some levels, but in a different presentation.
Nice graphics, very readable, everything works as expected. I think you did a good balance for the difficulty curve, the Unlock All button allowed you to make harder levels without ruining the fun for some players.
I really loved the various expressions the cat's face could take on.
It was original to control the coin instead of the cat. However, I don't really get the "Old Gold" theme in your game, only the "Gold" part.
I liked the soundtracks, I just think you could add more variation in the gameplay music, as I feel a lot of work was put into the menu music which isn't the most important part.
I managed to get 3 bells in every level !
Good job ! One of my favourites so far.