Looks nice, but it is not doable at all.
I think the challenge here would be to make something as nice looking as the actual game without going over the restrictions it is bound by.
If you look at this, these are all the base tiles used for Area A (plus some more for tile animations on stuff like the fire, but this is a good base for how many tiles you have to waste)
Things to keep in mind:
- 4 palettes for background consisting of 3 colours each + global background colour (black in most games)
you are mixing around quite a lot.
- Try to keep stuff on tile boundaries (collision and all that and again more colours than possible, girder!)
- Try to keep your tiling efficient and do not make tiles which have only 1 pixel in them and are otherwise blank (stars, some of the windows)
- Same goes for the stuff on the houses where you have a tile which is sky and 2 columns of pixels on the left, this is a wasted tile taking the restrictions into regard.