I think that I did not make the brightness between the top and sides big enough of a difference and the tiles look somewhat washed out.
Yeah..
You really should do something about that. It's the most obvious issue.
The stairs also look rather flat, you need to add more depth by darkening the steps and lighten up the railing.
Also, you should make everything thicker horizontally to further enhance the perspective, stuff like the legs of the table for example. Because it should looked squashed down.
To take the perspective even further I suggest gradient effects like on the book shelf.
Good job on the highlights and the texture!
