I'm not a music composer, just a listener, so if I seem to harsh sorry lol.
I see where your trying to go with the guitar and stuff, but you need to make it sorta sound like the song =/ Like at the beginning I recognized it.... but like 15 secs later it changed into something new, which is what normal remixes do. Though halfway I'm thinking to myself "What part of the original song is he on now....?"
I dunno, To Zanarkand is a song with a lot of emotion. I recommend putting emphasis on the piano in the begging, to remind the listeners what it is they are listening to, then add the guitar and drums, but then suddenly have the piano comming back with the other insrtuments (ex: Some of the kingdom heart songs).
I dunno, either way you composed SOMETHING which is more then anything I'll ever do XD I can see the potential in this song, just remeber you're remixing so be sure to show signs of that solemn soundtrack. =D