I like the little guy floating in space. xD

interesting perspective - the hole in the floor makes it seem like the platform is actually suspended above the deck, like where the captain of the ship would command the helm.

you should take out the text "observation deck" on the floor i think

-pv

The perspective on this piece is a little off. You see the chairs almost from the top, but then you see the desk and the windows almost from the front. I'd work on that if I were you.
Other than that: nice colors and vibe. :)

Good job with the pixeling. You have a very interesting idea. These are my critiques:

It is very noticeable that, on the outside tiles, each 4x4 block is repeated. Since you have 16 different tile types, why not randomly distribute them on the whole floor?

I don't understand the perspective very well though. At first, it seems like a top-down view, judging from the wall top borders. Then it looks like a diagonal view for most of the rest, but then it's also almost a front view on the desk thing in the middle and the detached piece of street in the right hand of the pictures. The shadows for each element are different (compare the shadows for the desk and the chairs, and also the stairs, and also the shadow the floor projects onto the subterranean floor), so it doesn't help too much either.

Since it's outdoors outside of the window, you could also create a nice shadow effect if something was shining through the window and into the room, to create like a main shadow that dictates how all the rest work.

Keep up the good job!

Yuji