Thats really confidence building thank you so much! Yes the last one was to teach you more about the Orange blocks behavior in the 2nd Dimension, they sort of override the 2nd Dimension by applying Depth (hence why you cant move past them even in the 2nd Dimension).
if you spatially position yourself via the 2nd Dimension, in "Front" of a Orange block, you are actually in front of it - due to depth they add which, the 2nd Dimension doesn't have. So you hit it when returning to the 3rd Dimension (Isometric Overview) and because there isn't anything below you now (in the 3rd), you fall down.
God thats difficult to explain (could even be illogical), wish i had more time to develop and teach the player these consequences and rules slowly but I had to squeeze everything down to the most interesting things I could find and fast. I will do better next time!