I played the movement and combat demo, and liked how the mechanics were explained one at a time. I got to the part where there were a bunch of monsters to kill, and I did that. Then there was a part where I needed to jump but I couldn't (pressing space didn't do anything). I figured that maybe I needed to stash the sword or something, so I pressed G, and the game closed?
I liked the shadow effect from the flames, and also the blurry effect when swimming underwater! The length of the swimming was just right that I was close to running out of breath, but made it, so that was very well calibrated.
For the level generation demo, it was pretty cool to see a procedurally-generated level, but I wasn't sure where the key was. Maybe an arrow of some sort to point in the general direction might be good?