This is Incredible!
The presentation, sprite work and music is so good that I definitely would've mistaken it for an official Game Boy game (I especially love Gateau's design and the cute meows in the soundtrack).
The gameplay loop of collecting gold and escaping carriages is a simple engaging loop with tons of replay potential and kind of feels like a roguelike. I think it's a cool idea to have levels be randomly generated while still having difficulty progression (especially after level 20 which I still haven't overcome). Most of the levels are well designed around platforming and the transformation mechanic, both of which are clearly taught early on without words. It is a bit frustrating that you can't heal and dying means going back to the beginning, but I can look past that as I know this is an endless game (also skill issue for me).
I was a bit confused by the ranking system, though as I thought it was based on how much gold you collect, but I ended up getting an "S" after dying early on in the game despite not collecting that much gold. But that's my only major issue aside some level repetition.
I'm happy to say this is one of my favourites from the jam, thank you.