The rumors were true: Nintendo games can now play themselves!

[theRepublic]

Reasonable said:
Sounds interesting, but really what ever happened to 'easy, medium, hard, insane'?

Also, while this solution sounds elegant, in most cases difficulty spikes are the result of a balance issue with the game design, and I'd hope that identifying and removing these during testing would remain a focus also (i.e. the problem with this solution is in some ways it covers for game design errors).

Someone else in this thread said something like this, and I will ask you the same question I asked them.  How exactly to you impliment difficulty levels in a platformer?  You can't just add or subtract health from the enemies like some other genres.  Even the number of enemies is rarely the issue for platformers like Mario.