I like it.
Although it seems to me it's a bit too mellow for a boss fightish scene, maybe add a bit of guitar during the organ, to kinda give it that feel of hopelessness and inferiority. Kinda like how "Divine Madness" worked out, didn't use guitars or anything but still sound very intimidating. I know this is still a preview and it's good but I honestly can't wait to see the final piece.