Anyway Gil, FF isn't iso.. you obviously don't know what iso is.. so yea...
Obviously. Isometric, for your information is anything without vanishing points, with vanishing parallels, which your piece obviously is supposed to be. However, the way you handle it (projectional) looks way wrong, and makes it look flat. I suggest you don't use square floor tiles, unless you're looking straight down on them...
The meaning of isometric is, simply, "of the same measure." (or of equal dimension)
However, in regards to pixel art (as helm mentioned) isometric refers to 3/4 perspective.
Let's not confuse our terms.
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Anyway, in regards to the piece, the middle alteration of the sprite perspective in Turbo's edit looks the most correct to me. The proplem is the back wall doesn't seem to be in the same perspective as the trash bins. The wall could easily fit into a platformer, with no major overhauling. Either the trash bins need to be changed, or the wall needs to appear as though it is being looking down upon, rather than looked forward at.
Also, it might be in the piece's best interest to expand the canvas upward, and fill in the 'top' surface of the wall, to give a little more insight as to what is going on with the overall perspective.