Well, first let's point out the first blatantly obvious thing. The samples you're using are little better than MIDI which, really, is a no-go. The whole thing just felt MIDI standard, there was no expressive qualities to the instruments where they really were gagging for it later on (1:33 in particular). Basically, I vote getting better samples- or a better program altogether.
However musically you're obviously good, there are chord sequences in there that were obviously not in the original, however they sounded better. (However I do think, at 0:13, you should put in an Eminor7, Ebmajor7, Dminor7, G7 sequence in. I wanted it badly.) The instrument writing got alot better as it went through and I found myself liking it- especially as it reached the third section where you diverged from the source and back into 1:33.
The ending was also a bit weak, needed more. Basically, you need better samples, a better program to write them in and to definitely diverge from the source just that lil' bit more. You'll do fine, you can tell you understand music anyway ^__^
Hope that helped a lil'!