I know this is a bit late haha, and you might’ve figured it out by now, but anyway here’s how to do it:

• use up your lives and get a game over
• when the screen that says “game over” comes on, hold UP and which ever button you use to jump, at the same time.
• only works on the first level of each world (1-1, 1-2, 1-3, 1-4) if I’m not mistaken. I got this info from this guide here: http://tasvideos.org/5789S.html