well...
the only thing that you really did here is "rap" over a song that you didn't make. Granted, it was clever in a sense - but it ends there in terms of originality. The least you could of done would have been to add some of your own parts and fx into the song to give it some variation.
I'm not sure about #1 spot either. I suppose not everything can be "Ultimate Showdown" quality, but they should at least keep me satisfied. A good effort for what it is nonetheless.