So, I have been thinking about this for a long time, so here it is.

In Chapter 1, you have to collect three flags in the palace for Whistle Wishes. Normally, as far as I'm aware, the blue unicorn will always go up, blocking your path to the flag directly. Luckily, the hitbox of the flag makes it more forgiven. The yellow unicorn is easy to dealt with since she only moves down AFTER you obtain the second flag. The worm in the room with Princess Cherilee will move down, so the player must go straight and go down-right to get the third flag. This is most annoying part because then, you have to go back up-left and go straight.

Now, for the juicy part. For some reason, if I can recall, if you position Rarity just in the right spot when transition to the next scene, the blue unicorn will instead go down, giving you a direct path to the first path. However, the second one will instead go down after you're in the room for about 3 seconds. Luckily, there is a zone where the second unicorn cannot enter, I supposed, so with the hitbox of the flag. The third flag can now easily obtained because the worm would stay stationary, which gives you a direct path in and out of the room.

I think I did got the manipulation in the WR and the video I'll be published in my new channel (since I forgot the password). The reason I called it 'possible' is because right now, as of I'm writing this post, there's not a consistent setup yet and really lack of understanding of this.

I may look more into this.

You're right. Still, a good finding on this. All we had to do is to find them.

Also, one more thing to add, you can skip the cutscence where Puss said, "Look, those dastardly pirate has stolen our sails!" by jumping over the area near the second pillar. I don't why, but hey, if it works, it works.

That's a nice finding. However, as you mentioned, it only work only in PC, which can put other consoles, HD or SD, in disadvantage. So, that's why I found a consistent setup to preform the Pirate Ship Clip (the source should be in the Forums page of this game). This is only a theory, so take it with a grain of salt: I believe the clip works because of how you position your character. The reason why the setup for the Pirate Ship Clip works is because it just so happen that I'm at the right spot. The game detect if there's a wall behind or not. If it does, you cannot parry jump, as I would call it, through the wall. However, if position correctly, you can confused the game into thinking that there isn't a wall there, where in fact, it was.

As for yours, I think the collision is FPS dependent. The game runs on 30 FPS or 60 (I'm not sure), so when in lower FPS, the collision wasn't there because of how the Havok engine work.

Again, this is just a theory, so take it a grain of salt.

Source: https://www.reddit.com/r/speedrun/comments/i9zzgy/a_consistent_setup_to_preform_the_pirate_ship/ A little context here:

As I mentioned in the video, I found a consistent way to clip through a particular wall in the Pirate Ship level. Here are the step:

1. Run head-on to the small ledge until there's a smoke coming out from Puss's feet but he isn't moving forward.

2. Perform the block (R trigger) and turn around about 90° to the right.

3. Walk forward and perform the block such that Puss's left paw touches the right side of the third screw from the left as shown in the video.

4. Perform the parry jump (R trigger + X) and ground pound (X button + Circle button) once you touch the curved wall.

5. Still in block mode, turn Puss so he faces to the camera and perform another parry jump.

If done correctly, it should clip Puss through the wall far more consistent, save about 2 to 3 minutes by skipping the lever to pull down the wall and its associate cutscene.

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.

Reference to this: https://www.reddit.com/r/speedrun/comments/hxhw9o/clip_through_the_wall_in_shrek_the_third_psp/

As of I 'm writing this post, I have yet to found a consistent way to preform the clip nor any usefulness to this other than maybe a few seconds from Prison Cell Block section and the end of the High High Peak section.

For the Prison Cell Block section, you can clip through the gate that leads to the three button puzzle, right after you fought the tree enemies. I found this one to be the easiest to clip through as I sometimes clip through the gate first time without any setups.

At the end of the High High Peak section, there was a section where the door to the end of the level is locked and you were supposed to pull over the lever to open it. This would, in theory, be a huge time saver in the run, estimated to be 30 seconds or so, as you skip doing that. As of right now, I haven't found a consistent setup.

Possible time save: About 35~40 seconds.