This prototype has a lot of potential! The amount of care and effort you've put into this game really shows, especially in the details of the wonderful pixel art on display. The current gameplay is fluid, but it would strongly benefit from some additional features. I'm looking forward to seeing what directions the game takes with future updates!
My main criticism is that the protagonist has extremely slippery controls. The jump height is so high and the gravity is so low that I can just fly past the level and have no idea what I'm missing on the ground. The great character speed and inertia also make more precise platforming challenges a real hassle, and I struggled to land on the thin tree branches without the help of the vertical slashes. I feel like the game would be more enjoyable if the protagonist's controls are adjusted to be tighter with higher gravity or if the level design is adjusted to better reflect the protagonist's capabilities.