Staircases can zoom you through doors, strangely. I'm not sure if this works with all staircases, but it does work on the second-floor staircase leading to the clock area, and it works on the endless staircase! Go to the bottom of the stairs, face away from them, and do a long jump forwards (run, Z + A). Hold onto the Z button. Now, tilt the control stick in the direction of the stairs and continue to long jump. You should start to slowly long jump backwards. Now, when you land on the stairs, continue to do the backwards long-jump but hit A repeatedly. If you do it in just the right way, Mario should start to bounce rapidly against the stairs and shoot up them really quickly. He'll then zip through the wall behind the stairs. Strangely enough, this will work on the endless stairs, so even if you have less than 70 stars, using this technique will blast you through the infinity of it and bring you to the final Bowser. The strange endless-stairs music will continue at the Bowser area, although it usually doesn't.
Submitted by: Dom Dunc