I'm not an expert on mixing myself, but I would say that's your biggest problem here.
Your instruments all sound like they're playing at the same time instead of "together." THat's a real esoteric criticism, but that's the best my own knowledge lets me describe it. Part of the problem at least is just HOW LOUD THIS IS. IT'S LIKE IF I WROTE THE REST OF THIS COMMENT LIKE THIS.
You want more "room" between instruments so you can highlight the parts you want to the listener to focus on, like when your leitmotief shows up or when you break things down like at 01:11.