You're talking trash, Theres nothing hard on adding some cheap brushes on a background that is already made.
Change the blending mode and done...
Also the colour grading is just some easy contrast and hue/saturation...
Now lose the attitude kiddo, this is beginners work.
Whether it's beginners work or not this is pretty cool and the difficulty of it shouldn't matter when it's given freely to the community.
Unless you can do better than most of his other work, than I wouldn't be talking.