Okay, wow, the art here is utterly fantastic. It's really reminiscent of a PICO-8 game, like the original Celeste. The lighting on the dark side also looked so dang good. Both rabbits are also pretty cute and I liked how they're a nod to Japanese mythology. The sound was also really good.
I feel like the game would play a lot better if the springs detect you from above and not from the sides like they do now. It made the second to last level a lot more frustrating than it should be.
I'd also suggest looking into Coyote Time and making sure the ground detection works perfectly like the other comments suggest.
Overall, the game was great, and I'd love to see an expanded version in the future!