This works perfectly as a thriller/horror movie soundtrack. It's a track of dark energy, emotion, and dread. I rarely have heard a track this powerful, as Testificate 517. Interesting choice to make a three-parter out of it, but I must say, it works very well.
Part I might be the most intriguing for me, those church organs gently roaring through my headphones instantly puts me in a mysterious mood.
Part II is quiet and subtle, and also very psychedelic.
Part III is more energetic, bombastic, and very powerful in bringing a climactic feeling to you. I believe that, in your imagination when you wrote this particular part, something very important was going to/is happening. The sound design really helps this song upwards too. That's a recipe for a true masterpiece. So, 10/10 stars.