Thanks.
What part sounds off key? I don't really hear it.

I think I'll just tell you my full opinion about your remix.

Great choice of instruments, but don't you think that marimba could be substituted for something with a little bit more... "oomph"?

The quieter part is quite jarring...

The bass sounds disappointing. I think synth bass isn't quite suitable for this kind of song, if you're going to use trumpets.

The trumpets, as I said, are too quiet. Also, I wonder whether you could make it go with the main melody?

The percussion is good, but... I wonder whether you have tried having the percussion change positions?

I see that there seems to be a lot of instruments used in the MIDI file, but some of them seem to be underused. The French horn, English horn, rock organ and orchestra hit seem to be the underdogs of this song.

...You're right, nothing's off-key. Maybe I'm just too used to official remixes.

(Seems like the whole song is mono...)

Oh wow! Thank you!
This is the kind of feedback I need. Everybody is too afraid to tell me what they really think. I'm going to go work on it.