how can i write this in english?

Both are right. But the first one seems more verbal and not in complete sentence.
I will suggest: We got 80 for this project.
This project got marked 80.

Both are right!

The project got 80 points! also okay!

both are correct, depends on who did the project.
You can also write as
"Our project got an 80"
"We got an 80 in our project"
beside, we normally use "points" instead of "marks"