Initial impression after the tutorial:
It feels very polished from the start. I liked that you had a loading bar in the intro and that you added a gameoff splashscreen. I am currently playing on the web build with a controller(because you said that, that is the way to play)
During the tutorial there were no binds for the controller. It said press "space" instead of "x/a" and so on. This might be because I connected the controller later on or because of the web build or maybe you didn't have time to include text for different controllers. Managed to figure out the controls still.
The first room after the tutorial I killed my self multiple times with the expanding of the crate. It felt a bit frustrating in the beginning but now when I have finished the game I don't mind it. It felt really awesome the first time I killled a bat with the box accidentally. Managed to get a couple of double kills with the box later on :)
Water physics was a surprise, small details like that give a lot to a game.
Some bugs/improvement area.
You probably already know this but wrote some stuff down when I played.
Gate animation could be changed a bit. It feels like there are two animations, one opening and one closing. If the gate is currently opening but something happens (like I step off a button) and it needs to close then it will start the close animation from the closed state.
When you hover and attack the animation will go back to idle instead of hover.
The blue enemy that jumps can see you when you are under it and sometimes through walls.
The first area in the hover route or whatever(the door that leads to shadow boss) was a bit tricky for me to figure out. I had to watch the gameplay but I felt really stupid when I saw what you was supposed to do. I managed once to fly over with the box in my hand and quickly throw the box and slash so both the box and my character got through. I though this was the way but never managed to do it again. Not sure if any rework is needed here but I got stuck there a long time.
The fight with the minotaur was the hardest for me by far. It did not feel fair. When the minotaur is about to attack and you slide under and attack him, he will almost immediatey look at you and attack again. There was also a place wher you could stand without taking any damage in that fight which was nice for me but not sure if you intended it to be like that. Adding picture.
I think that if you take damage and then enter an enemys hitbox you wont take damage again and it will just stand on top of you. It happened twice for me with zombies.
One zombie once stood completely still even though I was close and in his range. Hard to see on the image but he stands still I promise 
It felt like the shadowboss couldn't hurt me when I stood on the platforms above. Like he never used the electricity then.
Overall a really nice game. Think I spent an hour on and I had a great time with some minor frustrating parts (like when I got stuck or when I killed my self over and over with the box). I liked that you used the boxes for the bosses a lot and I enjoyed the level design. However, sometimes it took a bit too long to backtrack to the hub. Great work!
Viewing post in Merlin: Scale of the Magic jam comments
Thank you so much for the in-depth review and the constructive comments! Outside of the improvement on the gate (which is really insightful, thanks!) we unfortunately were aware of the other issues when we submitted, but unfortunately ran out of time to fix them. In fact, the main reason the player gets killed by its own box is because I didn't have time to fix the subtle collision issues that can happen if there's not enough room to expand various colliders (things could fall out of the map without a way to respawn etc) so that was an easy cope-out lol
The minotaur was also completely reworked at the last min (used to be a skeleton a few hours before deadline and is still called SkeletonKing in the code :) but we didn't have time to make it fair and pleasant. Once you know you can slide under his legs (I tried to get the player to use the latest ability gained to kill the boss from the next level), the fight actually becomes completely trivial and is just as non-balanced. This is something we'll rework in the postjam version. There's also no help for the player to understand how to beat the boss as well.
In any case, thank you so much for going through the game in its entirety, it means a lot, especially knowing those areas of frustration :)
Cheers!