Huh. I'm actually used to an arrangement that, while incomplete, is generally 'finished' up to the point that it's been done to. Not to say anything against your methods of writing, but it caught me off guard. I'm assuming the other parts are coming soon.
From what is here, though, I can tell this will be a fairly conservative mix that doesn't stray from the source too much. The ostinato might have a note or two that are not like the source, but I honestly can't tell because the delay drowns the notes out. You might want to lower the wetness or volume of the delay a touch, not so much as to lose the effect but just enough so the base instrument can be heard clearly. There are a couple of spots in the other instruments where the delay bleeds unintentionally into different sections - minor, sure, but it's best to catch these things early rather than leave them for later.
The theme at 0:53 is a third below the source. Whether that was intentional or not, I can't say, but if you were trying to sound like the source then raise the notes up by a third. Compare your track to the source and try to match it.
Otherwise, I can't say much - this is in a state where I can't really provide too much useful feedback. Good luck with it - Laguna always had awesome battle music, so it's nice to hear people remix it.