Hmmmm... I don't know about technical details or even enough music theory, but I'll say what I think, and here goes nothing!
I really liked to listen to this song, and after some time it made me remember the tension that I felt everytime I did set foot on Norfair while playing Super Metroid when I was a child, almost 10 years ago. I don't see any need of improving anything, the remix is good, pretty good, catching and, of course, it's epic! Maybe it's just because I'm not a musician and/or I don't know what good things can be done while remixing a song, but I really think that this one here is good to go.