I wish trees and walls were a little more different, because when you're far, it gets really really hard to understand what's what. Or maybe some kind of effect to help understand distances, because everything tends to blend together.
Some dialogues are a little too long.
And as other said, once you visit the area with the locks, the game starts lagging every time there's slimes around. Also it's a little frustrating to open a door and finding another lock behind it, having a thing with three locks, clearly saying "you need 3 keys" would have felt better.