This is so cute!! The music fits well with the art style and theme.
Spreading and butter, plus the butter mechanics is a very fun take on the theme. I was impressed by how nice the character movement felt on buttered floors and walls (didn't expect to ever type that sentence! lol).
I'd consider the level design for future polish. At the moment, I'm just aimlessly searching for bread--finding some way to motivate the player to go places and utilize the mechanics to get there would be great. You could improve that in a bunch of different ways with the art style, level design, story, or any combination of elements.
Great job on your first game--I had a nice time playing it!