Here is an overview of the game, via Nintendo.com:
For resolving lack of daily exercise and strengthening your physical strength!
You can enjoy authentic exercise in the world of Fist of the North Star without changing the functions of Fitness Boxing!
Familiar characters such as Kenshiro become your instructors!
In addition, a new battle mode against rivals has been introduced, allowing you to enjoy the exercise with enhanced action gameplay.
Punch your way through the many enemies that stand in your way, and aim for victory in the boss battle!
Watch a set of trailers below. View a set of screenshots at the gallery.
“Fierce Battle” Gameplay
Character Trailer: Jagi
Character Trailer: Kenshiro