PR2 Speedrunning Guide

[Master Raiden]

Moving Diagonally
Your horizontal and vertical speeds are independent which means your horizontal speed is not affected if you are also moving vertically. Because of this, you can cross diagonals in the same amount of time as it takes to move horizontally or vertically by the same amount which allows you to cover more distance in the same timeframe.

Diagonal vs Horizontal Movement - Illustration

The paths to the lower (Red arrow) and upper (Black arrow) Finish Blocks are shown. The lower Finish Block is closer to the starting point than the upper Finish Block, however, both can be reached in same amount of time.

Diagonal vs Horizontal Movement - Example

~Fantasy World~ by gerben (6134067)
Jumping as early as possible to break the brick (Red arrow) is faster than waiting until you reach the Arrow Block (White arrow).
Since the Brick and Arrow Block are in the same vertical column, a player running to the right will be able to reach both of them in the same amount of time. Following the Red arrow will allow them to break the Brick while a player following the White arrow will have only just begun their ascent to the Brick.

Moving diagonally is essentially the combination of two movements at once, one horizontal and one vertical.
If you stop moving diagonally, that means you have stopped moving in at least one direction which can cost you time.

Breaking Down Diagonal Movement

Perfect Storm by Colind (6202240)
Depicted below are a perfect diagonal fall (left), moving too far to the right (middle) and falling too far down (right).
The White arrows show where movement is ideal and the Red arrows show where time is being lost.

  

Since the crawl space is below and to the right, it is best to move downwards and to the right as quickly as possible without slowing down or stopping in either direction. This is what a perfect diagonal fall achieves.

Moving too far to the right does not save time since there will still be some downwards distance to cover.
Falling too quickly does not save time either since there will still be some horizontal distance to cover.
So a balance must be made so that neither direction is required to slow down too much.

Knowing Your Direction
Knowing which direction you need to be moving in, and optimizing your movement to allow yourself to begin moving in that direction as early as possible will smoothen your run and save you some time.

Levels are often not completely straightforward. There will be jumps that you have to make, drops that you have to fall down, and switches in direction.

Because of this, a balanced application of the previous tips may be required to achieve the optimal result.

Balancing Speed Conservation with Early Acceleration

The Time Machine by Sanzep (5981302)
In this part of the level, the player must fall down a narrow section, then continue moving right.

On the left is an image illustrating the two key clipping points. The upper point is the one that a player must pass before they can fall into the gap. The lower point is the one that a player must pass before they can begin moving right. How do you optimize your speed for two different clipping points?

The middle image depicts a trajectory optimizing speed past the first clipping point. By performing a high jump, the player can begin accelerating downwards earlier and maximize their downwards speed. However, due to the tightness of this section, falling quickly makes it difficult or even impossible to avoid the lower block, so the speed cannot be conserved. The player will lose all their downwards speed temporarily before falling slowly again past the second clipping point.

The right image shows a more balanced trajectory. By performing a smaller jump, the player falls more slowly, but they are able to conserve their speed and carry it all the way to the bottom.

Ultimately, what matters most in this particular scenario is how quickly you can pass the second clipping point and begin moving right. Maximizing speed past the first clipping point does not achieve much unless it also helps you pass the next clipping point more quickly. So the direction of movement that should be optimized in this case is movement to the right, and that can be achieved by sacrificing a bit of downwards speed.