My first project hard rejected... Review please

Hello everyone,

This was my first upload. Motion backgrounds, a pack of 10 loops.

25fps
H264

Preview link: https://youtu.be/-9ZXXRe5dvo

I just didn’t understand the reasons for rejection.
Can you please give me some feedback and clues?

be warned envato many times! Particle and similar studies will not be accepted. You should add more things to your project.