After you get to the halfway point in the level while the platform moves up and down use diddy kong to cart wheel off and jump as far as you can and if you jump in the right place there is a secret barrel that will launch you to the end of the level but make sure that you hold left once launched otherwise you will loose a life and it will take a few tries because the barrel is located just above the second barrel that launches you to the halfway point and make sure you have at least 20-30 lives. I have known about the cheat for almost 12 years but I am not sure if nintendo knows or not.
I was fooling around one day and I discovered it by doing that by mistake because my thumb slipped of the b button so I just jumped over a bit hoping I would not loose a life and all of a sudden I was being launched all the way to the end of the level.