Hello, I’m Uğur KILCI, I added my first HTML theme to Themeforest 4 days ago. But it was rejected. Where did I go wrong? How can I fix this error? I need your experience and suggestions. 
Hi @ugurkilci and welcome!
This seems like more of a cool concept piece rather than a full-fledged theme.
I would also steer away from using a major brand such as Minecraft to show off your work that you intended to sell on a marketplace. Sometimes you can get around the legal issues, but it’s always better to make something original, and in my opinion, piggybacking off of an established brand looks cheap.
I could see this concept as being part of a larger game-oriented theme, maybe even for an escape room where you have some puzzle info around a cube like this, but not as the entire site/theme.
Not using a brand name is a better option. Okey. I understand. So how do you think this cube design is? Do you think this design can be sold?
Not on it’s own as a theme. Like I said, I think this would be put to better use as part of a larger theme.