The aim of the game is to combine words you already know in their various forms in French (masculine, feminine, plural). And in French, "du pain noir" is not only rye bread but an expression "manger son pain noir d'abord" meaning "having hard times first - to enjoy better times "pain blanc" afterwards, coming from the times when white bread (refined wheat) was reserved to rich people.
Noire and noir are the feminine and masculine (respectively) forms of the same adjective.
Most common nouns in French are masculine or feminine. The form of the adjective changes slightly depending on whether it modifies a masculine or feminine word. Masculine words go with the indefinite article "Le" and feminine words go with the article "la."
If the adjective black (noir) is referring to a masculine noun, e.g., le chat, it's le chat noir (the black cat).
If it's referring to a feminine noun, e.g., la jupe, it's la jupe noire (the black skirt).