Interesting approach!
I had a few problems:
When planning, I could only see X/Y, not Z. Some way of looking at the level from the side would have made sense.
Using tab and enter felt strange. Could not the same button have been used for most actions, because they were sequential anyway?
Showing mouse in menu, but not being able to click was also strange.
Other than that, very cool entry. Amazing UI work! There was a lot of stuff happening, felt very alive. Good job!