It´s looking great! You could also play with block displacement, having blocks that don´t move like you said, that move in the opposite direction to the rest, or that move continuosly independently to perspective changes. Another type of block could allow the player to climb it´s side, or make the player stay glued to it when changin perspective. Also, blocks that can´t be stood on in certain perspectives,So right now I'm focusing on getting the escher blocks prettied up ie movement transitions and shadow transitions. Here's a gif of my escher test level. You can see the shadows aren't quite convincing/smooth, and for some reason shadows are casting through the blocks. Need to figure out whats up with that.
Once that's finished up I do need to come up with more ideas. Right now one of them I have is having a block type that doesn't move relative to the camera, so when you rotate it could bridge a gap you need to cross. Do you have any examples of what you mean by changing behavior/state? I'm all ears.
You have 2 mechanics: basic movement and perspective changing, so think of different ways to make them do different things, affecting (or not) the player, the blocks or both of them.