Sweet game! I like how the slot machine mechanic looks and it's pacing as well as your work with the lighting and occlusion. The two-tone color palette accented by the dynamic lighting gives the world a neat and somewhat mysterious feeling. I was feeling like some fog could work well in this world.
As far as the platforming mechanics go, I really appreciated how snappy the movement was, even in the air. It almost felt like Hollow Night. If you're going for the consistent speed feeling, I think maybe the max speed could come down a bit because as I was trying to land on the platforms, I kept over adjusting and running off of them. The other point of confusion I had was I wasn't sure if the buffs coming from the slot machine were stacking or just one at a time per level. It would be nice to have some sort of UI that shows the player what their current buffs are.
It's always nice to see a fellow Godot Developer! Keep making games!