Okay, I still can't find a way to replicate the skip yet...but I have a possible theory. After you switch the lever to open a locked door, there will be a cutscene and then Arthur would stand there, waiting. If you somehow die, Arthur and the lever would disappear but the door to the end would not. So, I have some progress. First of all, there is this place that is between Arthur and the archway that leads to the the door. When I parry jumps into that place, the collision between Arthur and the wall, if position correctly, will push Shrek upward when you preform a jump (in PSP version, that would be the 'X' button). If there is a way to not only make it work but also make it consistent, then, High High Peak Skip would be plausible. However, we also have to taken account that all version of Shrek The Third ( WiiU, PS2, PS3, PSP, X360, PC, Wii) works differently from each other. So, it might be possible that this may be exclusive to some version.