Agreed with Pipi, it stagnates as it goes. I would push for more of a solid structure, keep the melody mostly dominant, and let the chaos come more from how you work around the rest of it. If you want more of an apocalyptic feel, why not make it minor?
I also agree about the pad changes and register shifts, it seems very out of place. I don't feel that the whole project needs to be scrapped, but it does need very, very heavy revision. If you're looking for chaos in music, I'd say to listen to the soundtrack/style from Artstyle: Aquia. It builds and gets nuts as it goes, taking a simple melody just built around a simple scale and turning it into a monstrosity with vibrant energy once you get to the end.
That's chaos in the best way possible.