Classic beginners blunder. You need to give us a build not the source code. If you don't know how to do that you can look up "how to build/compile a project in unity"

Now to the game. The music is disappointingly quite. I want earrape volume when I hear the soviet anthem! Platforming was way too hard for me. The crappiness of the characters provided for a few humerus moments.

you downloaded the source of the unity, not the build of the game.  The game is impossible to rating.