Describe N+ here.
The chain of curse words would never stop, man.
Now, N itself isn't that bad. It's difficult, but that's mostly due to the inherent One-Hit-Point Wonder-ness of your avatar, a tiny little ninja-like guy who wants gold.
The long and short is that it's a timed platforming game where the objective is to get to the goal. Your score is determined by how much time is left after the five rounds are completed.
Remember to pad your controllers before you play this game. They will be thrown.