Okay so you did pretty accurately hit most of the notes from the game, but you coud've used a midi file so I can't say much for that.
See the trouble is I can't tell if you're going for a realistic feel or just trying to make slightly updated version of the track. The thing is the low bit version of this still sounds better.
I think I'm gonna point you to one of my favorite examples a doing a lot with a little, my friend Taylor Mefford used an assortment of free soundfonts to make an amazing score. It shows you how much you can do with fx and such to make convincing instrumentation.
I would also check out ocremix.com, they have a few helpful materials on this kind of stuff.