I've talked a little about 3D Worldrunner in the past. It's a 3D game on a system that's not really supposed to be able to do 3D, which makes it a little on the tough side. And that means that you're going to end up seeing this a lot.
But fret not!
If you hold Up on the Control Pad + the A Button + Start, you can continue at the beginning of the level where you left off!
Meaning you can keep plugging away at the levels until you either finish them or you give up in frustration.
It's really a no-lose situation.