Yes I've unlocked "The Kid" multiple times.
Those three levels are my favorite three levels of the whole game.

I completed the three levels in under 2 minutes with only 2 deaths:

http://www.youtube.com/watch?v=1ynYaRcuQpY

Video is off my phone...
So once I get my capture card working I'm going to record me doing it with no deaths, hopefully.

SMB 2 WHERE ARE YOU???