But think of regular chess as two dimensional, and think of quadchess as multi-dimensional. Two to four players can play. Normal chess complications are compounded when a player only gets one turn in four. Much more can happen. Much more needs to be anticipated.
Kings can Queen.
Frozen pieces make games unique, allowing or thwarting normal tactics. Yet this game can still be played at various levels of competency. In the talking mode, experienced players can coach others, which makes this a good game for youngsters who are learning how chess is played. But even more important, unlike regular chess, this game tests emotion and character. You learn a lot more about the other players and about yourself.