Prelude - Very nice here. Bad Synth out Harp in. This wins.
Hurry - The ticking was a little too loud and made the off-beat melody sound more off-beat than usual
AVALANCHE Theme - Good job. Sounds like the original with better instruments
Tifa's Theme - Too soft. I don't mean the volume. The original was some synth flute and you made it a violin with flowing notes. Make the notes more harsh or change it back to a flute.
Battle theme - Missing the mechanical edge in the background. Notes need to be more defined I would assume
Turks theme - Sounded good until the Bass came in. Alternating the left/right audio channels hurt my ears when I was wearing headphones
Boss battle theme - This was my least favorite. I don't mind the orchestral sounds, but this really does require a metal guitar as the melody
I can't remember the names of the next two, but I liked what you did with them.
ShinRa Corp theme - I like the power this suddenly gave the theme. This is good too.
Overworld - I love even the original of this and almost all remixes end up the same, but still very nice.
I really like what I hear. I can't wait to hear the rest.