In the first line, “game” refers to hunted food. J-Franks is not killing the rap game, in fact, he is bringing it back to life
In the second line, however, “game” does refer to the “rap game.” The word “doe” refers to a female deer (thus, “the game so dear to me), connecting it to the first line in which “game” as in food is mentioned
J-Franks says he wants “the fat doe” because “doe” in this instance refers to “dough” as in money. “Fat dough” would mean a lot of cash
So basically, in two lines, Franks has a plethora of double entendres