Questions & Answers about Najgorszy problem z tą grą to zbyt długie zasady.
The preposition z (“with”) always governs the instrumental case.
• gra (noun “game”) becomes grą in singular instrumental.
• To specify “this game,” you add the demonstrative tą, which is also instrumental feminine singular.
Adjectives agree with their noun in gender, number, and case.
• problem is masculine singular nominative.
• The superlative najgorszy takes the masculine singular nominative ending -y.