Play as Chunky Kong in the Frantic Factory level. Go into the testing level 
of the place. Find where there are three yellow Banana Coins (Donkey Kong's) 
on a stairway. Face the stairway, then go to the left and you should see a 
block that has a rising part out of it. Jump onto the rising part then jump 
into the little crevice in the wall. Jump out of the crevice towards the edge 
of the barred platform (the upper level of where the yellow Banana Coins were). 
When you are right at the edge, do Chunky's aerial somersault towards the edge. 
If done correctly, you should be inside of the platform and still able to 
move around. To get out, simply jump or move over to the top of the stairway.