You kidding??? That thing probably only took 5 minutes...
But whatever. The theme isn't the issue, I agree. It's a good, relatively unique one, and a good tileset could be made with it. I really don't want to start all over, either. Perhaps I could have a go at modifying some of those tiles, but all I really do is blur them with a dark outline.

EDIT:
This is sort of along the lines of what I mean:

You get a cartoony look, but you instantly lose all the texture detail.
Oh, and while the original uses 281 colours (for those three tiles), the modified one uses 1,340. Colour reduction is going to be a nightmare for this set.