I think this has so much potential and I you could make this into a commercial game eventually. I love how you set up the story in the beginning and the sound effects were very cute. The only issues I noticed were some jitters when moving diagonally, y-sorting problems, and hitbox problems. I LOVE that you added leveling up abilities and the enemy encounters were fantastic!
The game is super fun and I would love to see what you work on next or if you continue updating this game.
As far as the issues I mentioned:
I'm not sure, but I think that the diagonal jitter issues are due to not normalizing the Vector movement for the player (not sure if it's the same terminology in Unity) or from a Vsync issue. I've had similar issues in the past when making 2D games but I don't remember what the exact solution was.
Some of the terrain tiles appeared on top of the player regardless of the player's position (especially noticeable on the bush tiles). I don't know how to set up sprites in Unity, but there's a sprite origin in Godot that determines where the cutoff point is for sprites that are behind or in front of other sprites and this might be the issue. I think this is just called the sort point in Unity.
I noticed that the player hitbox seems to take up the entire sprite, which causes the player's head to crash into the trees and rocks and makes it easier for the slimes to damage the player when attacking from above. Usually the player hitbox is set to the lower half of the sprite so only the feet and maybe the torso can collide with objects, but I could see how doing it this way makes the Y-sorting issue less noticeable.
I hope this helps! Anyways, amazing job 10/10 <3