The shadow on the boxes are good, its the faded inprints on the carpet and pictures that are wrong, using the pencil tool, not brush is best. Perhaps you have the AA checked "on" and did not notice. Again use the little -+ thingy below your artwork to inspect the pixels. I too use photoshop and only wish to help not put you down.
By the way there is no such thing as a round brush that is 1x1 pixels.
Masser, I regret to inform you that this is not "pixel art". The AA on the boxes and particularlly on the carpet are so obvious that they spill out unto the black line (use the magnifier). I regret the 4 rating I gave your piece earlier. Please re-make this since the idea is good and re-submit it soon before the really nasty pixelnaxis catch you. WELCOME TO PIXELJOINT
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