nah skittles, good crits overall, keep it up.
I'd say if you want a good result (i mean like pixel golden stamp of approval good) you'd have to do a complete rework BUT
what you've got there right now is atmospheric and clear enough, so don't lose hope.
Now, what software are you using for making your images? Right now everything is a blurry mess AND pixels vary in size, so format-wise this is a total wreck (you asked for meanness, haha)
A lot of this is just smudged brush strokes in photoshop or whatever, so I can't crit that, but the whole piece needs some unification colourwise, needs a clearer sense of what colour the sunlight emits and thus what colour the shadows get, instead of these straight colour ramps that are there right now.
I like your character. Can you post your character in original size outside of the background? If you do I'll give him a separate crit.
For the background, well, first of all, remove the smudgy stuff and repixel with pure pixels (preferrably in an indexed mode, that is to say, for example pixelling in graphics gale with 256colour mode turned on) and post it again and we could help you from there!
Good luck, and still, good overall sense of atmosphere. If you just get it together with real pixels you can get far with this, I think.