I really like how open the world is and how you can choose to explore, talk to NPCs, fight monsters or go straight to the boss. The world is beautiful and the 3D models look very clean. Overall you've done a great job.
On the other hand, a number of small problems add up when they could be fixed very easily.
Firstly, the camera. The problem is mainly the fact that the controls are inverted compared to pretty much every third person game, so it takes a lot of time to get used to.
At first, I was very confused. I tried to kill some enemies, even though I didn't know what I gained fighting them. The magic abilities are unlocked after a certain number of "Imaginations," but the count isn't shown anywhere, so I didn't know what I should do. I would have really appreciated feedback when the player makes some kind of progress (like a text showing how much imagination gained, or XP, etc when killing enemies, opening chests or talking to NPCs). Since it takes so long to unlock the first ability and there is no feedback, I was really wondering if I did the right thing or if I missed something. If the abilities you unlock depend on the level of the character, then it would have been better to write "Unlocked at level X".
The first time I played the game, I collected everything I could, killed every enemy, and on my way to the boss, I fell in a tiny hole in the mountain where I couldn't jump, so I was stuck, and I had to reset the game and do everything all over again. There was also another spot where I could fall under the floor, so I had to run to the sea to get out. I think it would have been nice to have a reset button in case that happened.
The chests are weird. They open when you go next to them, but then you need to press F and there is no indication of whether you did something or not (except if you look carefully at the bar under the health bar). Since the "press F" text doesn't disappear and the weird glitched noise they make, I didn't know if the chests actually worked. Then I noticed that they make you level up instead of level down, which seems to go against the purpose of the game. But since leveling up seems to increase your attack damage, I went for that alternative strategy to fight the boss :)
After pressing play in the title screen, if you press enter or space instead of skip or continue, It shows glitched text, and the more you press enter, the faster the text appears. Nothing game breaking here but I thought that was pretty funny. Also, after beating the boss, in the final story text section, the skip button doesn't work and that made me lose time on my speedrun!
Sometimes when you fight an enemy, especially the "Shadow", the attack animation gets hidden by another animation, so you can't avoid it, and it looks like you take damage out of nowhere.
The fight against the boss is fine. I just don't like the way it sometimes teleports the player in the middle of the room because there is no animation indicating the attack will happen and it sometimes teleports you direcly into the spikes of it's other attack so it feels very unfair. Eventually, I found a way to consistently avoir the attacks but it looks more like a bug than an intended strategy.
Here is my speedrun of the game :)