Do you only get one turn to choose pieces (or forfeit and eat one type of slice) per cake? 3-5 players: Yes.
With the two player game the cake is divided into four pieces. Do you discard the unselected pieces?
2 players: No, you get 2 turns each. If p1 splits the cake, then you select p2,p1,p2,p1 and vice versa.