This game looks really good, the background and sprite look fantastic, the particle effects on the grass is a really nice touch, there are diverse areas and even a sewer and water area which is a lot of content. The world itself actually is MASSIVE, there really is a ton of content, an impressive amount actually but maybe a bit to much for a gamejam. The swimming animation is super cute btw.
Transitioning the music (And showing area names on screen) between areas is a really nice way to split them up atmospherically (Is that a word?). In general there is a lot of I think meta polish to this entry, lots of little touches that make it feel like a complete experience, even optional collectibles.
My primary feedback is on the physics of your character controller. Some minor feel touches like coyote time and a few other bits of gameplay feel juice would have been good, and the jump arc feels a bit to abrupt to me, gravity accel needs to be applied gradually imo to get a really nice feeling of hang time, but a lot of this is personal preference or minor tweaks that don't detract from the experience at all.
Really nice work, a fantastic entry!