I'm Not Sure
The first thing I noticed about the piece was that the Bass was too loud. The loudest instrument of a song should be the Melody, then the Bass, then the Drums, then the harmonies, etc.
The melody was very accurate, which I personally prefer in a Remix. If you can keep what's familiar and switch it up without writing a new song, you've got a good remix.
Saying that, the concept was good too. I didn't feel like you were grasping for an idea; you knew what you had set out to compose.
Unfortunately, originality takes a blow on this one. I see in your summary that you were going for the "NES" feel. But I feel like this piece didn't have anything to discern it from the original Nintendo song.
Here's my score:
Instrument Blend--- 0/1
Accuracy--------------- 1/1
Clear Concept ------- 2/2
Originality------------- 0/2
Appeal----------------- 2/4
Total------------------- 5/10
Other Comments - I weigh my own personal appeals heavily when I review. I had to take off points for originality and appeal, because this wasn't my style. But don't be discouraged! The piece was well put together.