Thank you so much! Yes there is a block so that you can't just walk up the stairs, but it wasn't intended to be invisible. I do see now that it's not very clear there is a block there, so I went in and gave it a different texture.
I actually never knew of the game FEZ until my friend made the same comment to me when I showed this to him haha. I really liked how they use perspective in FEZ, so I might have to give it a play through one of these days.