the second instrument to come in, near the beggining and quietly, sounded like it was a note off. Maybe you intended this, but either way, kinda kills the beginning. the last half reminds me of mario 64, the lava level.
also, the ending goes loud. you want the entire song to be loud, because louder is better (to an extent), also, you may want to mix eq's a bit so that all intruments can sound louder without making the volume louder, well, the volume needs to be louder anyway, but hopefully you know what i am saying. I really like what you did with the song overal though, it just sounds like an awesome song half finnished.
also, most of it sounds like it building to something epic, but nothing comes.