Wow, this is reaaaaally cool. the glich is when u r in Monkey Monysty, and destroy the Ice-Cage that a Yetti is in, move the cannon towards the wall, but keep it in the Ice-Cage Zone. now, press Square and FIRE!!! as you notice, the cage is Destroyed, but ya can't get through.

kinda fun, but there is a DISadvantege:

Disavantege: if ya get in when the cage is still visable, the game will ether Crash/Frezze