My Let's Play before my wall of text:
First thing is that I really liked this demo! Reminded me of Zelda and everything was solid for the most part. I can't wait for the changed music, even though the soundtrack sounds nice as is right now. There should be an asterisk on full controller support in my opinion since it wouldn't run when I plugged my controller in and had to use a 360 emulator.
I also ran into a few bugs:
When I tried to run past the spikes the first time, I was stopped like there was an invisible wall as the spikes went down, like I couldn't run too early or something.
There was another issue during the puzzle where I pushed a block all the way to the left wall. I tried pushing the block up but it acted like it was stuck so I would have to push the block back the other way so it would have room to move.
Other than that, I had no issues (the controller thing at the beginning was my own fault, not the game). I wonder what the finished product will look like since it has a lot of potential.