Nice wip there, as others have mentioned, I find the grass a bit jarring as it doesnt contrast too well with the rest of the graphics.
Well, some have said they don't like it, and some have said they do. :) I think it's OK, myself. I did quite a bit of experimentation to try and get the grass looking right and this was the best I came up with. It's pretty difficult making a decent grass tile that looks enough like grass but isn't too overpowering, and doesn't look like a carpet when tiled.At least no one has said the walls look like a giraffe, which is one comment I got at my end. :P