Anyone could help me understand what is wrong with it?
It’s far too basic
Needs significantly more premium features, functionality and design tidying e.g. consistent image sizes, better typography etc.
Code doesn’t validate as it is
Thank you for your answer.
I am agree that say @charlie4282 that your website is too basic bad colors, need better typography, need more navigation (about, portfolio, contact, etc) etc you need learning more you can see other example approved themeforest for give any idea. but you don’t can copy other website approved themeforest.