What's the difference between γνώση και γνώσεις;
(I am not a native speaker). Γνώσεις is the plural of γνώση. Here it is plural because the game requires knowledge of many things.
previously we learnt that "το παιχνίδι" means "the toy", but now only "the game" is accepted
Both words in English are translated with the same word in Greek. You just have to choose the most appropriate translation that fits the sentence in question.
Could γενικες γνώσεις be translated as common sense?