I have a hard time with this one. Not so much that I think it was copied from the game because I can tell there are differences. But the biggest problem for me is that it is so close to the original that it does make it questionable. Also if this was truely done from scratch in paint then your probably the most talented paint user I have ever seen. That fact alone also makes this questionable.
Either way this is still nothing more than a copy of the background from an SNES game and being so close to the original I have to wonder if it really belongs in the art portal. Now had this been some kind of hi-res version or had some other stylistic touches to it then it would not have been a question at that point.
Personally speaking though as a fan of the game I like this. But as an art portal viewer not so much.