I wonder what kind of text this refers to. Is it similar to a game manual, or really a literal description (like what you would have written in the box to give you a general idea of the game, but not going to detail)? Or perhaps just the specs?
Can "gra" refer to "theatrical play" as well?
It may refer to acting ("Nie podoba mi się jego gra (aktorska)" = I don't like his acting.
Rather not. Its „sztuka” or „przedstawienie”. Both are fine when we speak about actual performance on a stage. However when we refer to a script, only the first can be applied.
Does 'instruction' work for 'opis' in this case?
I'd say that "opis" can be a part of the instruction, but not the instruction itself. Also it can be a description on the box. Or on the Internet, even.
I never did.
"The game instructions " is valid
I'm not so sure whether 'instruction' and 'description' are the same thing. I mean, one is instructive and the other one is descriptive.