I'm adding details of how movement works in James Pond 3 as well as tricks relevant to the speedrun here for anybody who wants to try running the game.

-Movement 101:

First, let's establish some facts about movement speed. I haven't broken open the game's code to confirm any of this, but I'm reasonably confident after playing the game for months preparing for my run.

• James Pond sticks to surfaces when running. Rather than run off a cliff, he will run directly down it, with the same applying to upwards cliffs. All speed is perfectly preserved when changing running angle.
• Pond increases speed while running along downward slopes, and decreases speed when running up slopes.
• When running on shallow slopes or flat ground (anything less than a 45 degree angle), Pond rapidly slows down to base running speed.
• Friction (reduction in speed) is much lower for aerial movement than it is for grounded movement.
• Pond also increases speed while falling similar to the speed gain from running down a cliff.
• When falling onto the ground, Pond can land on any surface of 45 degrees or less. Landing on a shallow slope or flat ground will cut Pond's speed to zero, whereas landing on a 45 degree slope will attach Pond to the slope while also preserving all speed built while falling.
• Jumping adds velocity perpendicular to the surface Pond is running on. In practical terms, this means jumping while running along a downward 45 degree slope converts almost all of Pond's speed to horizontal speed.

This is a fair amount to keep in mind, but the basic methods of speedrunning can be boiled down to the following:

• Use gravity and downward running to build speed whenever possible
• Jump at the bottom of cliffs in order to reduce friction and keep horizontal speed high for as long as possible
• Jump right as you start running up a cliff in order to convert all speed into upward vertical speed, which allows for massive jumps

45 degree ramps are particularly important, because Pond can land on them when falling from height, but still gets to keep all speed built from falling. Jumping onto a 45 degree slope and jumping again immediately as you land allows for extremely fast horizontal speed, and is used constantly throughout the any% speedrun starting from the second stage, Camonbert Canyon. I call these ramps "Bumpers", because they tend to launch Pond around stages like a pinball when they can be utilized.

Capped and Stored Speed: Pond has an extremely rigid maximum speed, which I haven't been able to find any way to circumvent or exceed. However, this doesn't mean that speed above the cap is wasted. All speed in excess of the speed cap is stored, and that store is then drained before speed is actually reduced when doing actions that would slow Pond down.

In practical terms, this means that falling for 10 seconds and then launching off a bumper will allow Pond to stay at maximum speed for much longer than falling for 5 seconds and then launching off the same bumper. In other words, it's almost always preferable to get as much height as possible when preparing for a bumper launch.

Other Tricks:

• Dynamite Stalling: Dynamite is used to blow open two obstacles in the stage The Chunnel. Dynamite fuses are lit when the dynamite is picked up, and they're supposed to explode after approximately 4 seconds. However, if a lit stick of dynamite scrolls off screen, the fuse is unlit and preserved at its remaining duration. As a result, throwing dynamite in the direction Pond is running will send it off screen and allow the fuse to be preserved for much longer periods than usual, allowing the dynamite to be used to blow up a blockage it wasn't intended for.
• Phasing: enemies will flash for about a second after being hit by an attack, either from Pond's punch or a fruit gun. While an enemy is flashing, they have no hitbox and can be moved through safely. This applies to all enemies, even including bosses, however projectiles thrown by enemies will not be affected.
• Girlfriend Skip: James Pond's girlfriend is in the stage The Arran Archipelago. Colliding with her hitbox will play a short cutscene and add a forced menu display on the world map after the stage is completed. This is obviously a time deficit, so it's recommended to carefully jump over her to avoid wasting any time. I further recommend shouting "Girlfriend skip!" when completing the maneuver as a demonstration of mastery.
• Rocket Uncap: Rockets feature often in a few levels near the end of the game. By default, the rocket has an extremely low maximum vertical speed. However, that cap is removed if the run button is held when the rocket is picked up. Doing so will allow Pond to climb at the same speeds possible when not using a rocket.
• Rocket Efficiency: Fuel efficiency is a matter of some importance in the stages Gurgleton and the Wensleydale Wastelands. Experimentation is ongoing, but I've found the best results on fuel efficiency to come from rapidly feathering the ignition on the rocket, on-off-on-off, as quickly as possible. This will allow Pond to maintain height while getting the most distance possible out of a single block of fuel.