*Not a mod or judge, but I can give some constructive advice*
There are some ducking issues(resulting from compression probably) and I think the section starting at 00:53(Before the percusion and everything else kicks in) should be on different instruments, just sounds kind of odd/out of place for this particular song, why not try some more brass or another instrument instead of Oboes/bassons(?).
It needs a proper ending instead of a copoutfadeout also I think. And perhaps a little more variation at the end since you've already established by that point to the listener enough of the source to be recognizeable.
And production issues aside I think this is GREAT. There is more to arrangement than just changing everything so it's not conservative IMO. Song structure and the feeling of the original when it comes to pieces like this need to be preserved when arranged. Plus this is NOT 1:1 either, since it's adapted for orchestra , hence it's an arrangement, because if it was a straight 1:! cover then there would only be a small few instruments playing. It may be 1:1 in song structure, but definitely NOT in instrumentation and arrangement.
I am a HUGE HUGE Metal Gear Fan and I very much loved this.
I would just ease up on any compression you are doing
(srsly, orchestral pieces in generally do not need it. My recommendation is to take all tracks;unless you have sends , in that case it will take a little more tweaking; and drag them down -10dB,then render that file down to a .Wav and import that into a new project for mastering. And do any make up gain at that stage)
Do a tiny bit of tweaking to the sequencing so it doesn't sound overtly robotic
(Hint: In real life no one can play everything 100% accurate spot on, so lots of tiny little variations in performance sound realistic),
Do some EQ'ing to the low end as well as it seems a little unfocused/muddy
Just some constructive advice
The intro reminds me of what I did for Dwelling of Duels a few months ago (Because I did the Operation Ntrude as part of a jingle medley)
http://dwellingofduels.net/dodarchive/12-03-Jingle_Month/02-BONKERS-MetalGearSeries-DoDied-DoD.mp3