I like the pixel perfect graphics and animations of the knight. It's also a neat idea that the doors function as checkpoints. However, I'm not a fan of the control scheme. Atleast in my game you could use literally all of the keys ;-). All joking aside, it would be nice if the game supported WASD (movement) and JK (attack and alternative jump). Controller support would also be great.
A couple of the jumps are quite difficult to pull off. Like the one at the beginning were you need to make a couple of jumps to move from the ground floor to a higher level. At the area after that I fell down with the crate (you lied) and glitched into the walls. At first I thought this was intentional, but then the knight died (fall damage maybe). With the enemies I noticed that their dead bodies don't have any gravity, so they can float. I also discovered that the one of the bottom platform can glitch into the wall to the right of him. If you want to fix the glitching into walls, set collision detection to continuous (on the rigidbodies).
During the boss fight it was annoying that there was no health indicator for me or for the boss. I also found the fight to be too difficult. I retried the boss fight quite a few times, so it was a bit frustrating that I had to click through the dialog everytime.
To end, here's one of the difficult jumps I talked about earlier.
