Really nice idea! I enjoyed it. Reminded me a bit of The Stanley Parable.
Some feedback: I would tone down the motion blur just a tad and just double check the triggers when falling off the platform, I ended up falling infinitely a couple times. I really couldn’t see the hidden door in the flatlands level and only found it because of a comment here. The puzzles are good enough and don’t need the added difficulty by being invisible. Maybe you could have the outline render when a certain distance from the door? The graphics and sound design worked well together and the game has a great atmosphere to it
Overall a great game. Well done!