In level 1-1, in the third section, there is a staircase with a koopa coming down. Stand on any of the steps, and as he nears the step above you, jump straight up and time it so you land on him. You will then bounce on him as the turtle shell ricochets back and forth. Your points will multiply ala level 3-1 of the original Super Mario Bros., but if you bounce on him more than 11 times (at 1,000 points), you will start to earn negative 1,000 for each bounce. You can earn a total of 5,500 points this way.

Kick the shell after you get 1,000 and you will continue to accumulate points unpunished for every thing the shell hits. Flip into 3D and the shell will follow, so you can hit the hidden group of squiglets. Keep on following the shell as it ricochets back and forth throughout the level (you'll need Dashell to keep up--otherwise the shell will disappear) and you can earn over 100,000 points in just a few minutes.