-Floor tiles look nice, but too hard to tell from the foreground. Lighten them a bunch or use more pastel colours. Also if you only have the blak outlines on two edges, you won't get that double-line effect between them.
-The faded block things don't look like anything other than squares with faded edges.
-The sprites aren't too bad, but you might want to consider layering them properly so further ones don't stand above nearer ones.
-The thing on the wall is pretty ugly. If it's supposed to be a portrait, there's no way the plaque would be red marble with green text that's wider than the picture itself. Probably better to drop the joke than have it jar the player.
-The wall texture looks nice, but doesn't really work in a pattern. The doors don't match the wall style either.
-Normally it's not a big deal, but when you want feedback on graphics especially you should avoid using jpegs.