There are no known cheat codes, in-game options, or emulator settings that would allow you to change the character's movement speed.
However, you can try these workarounds:
* Use a controller with a slow-motion feature: Some controllers have built-in slow-motion functionality that you can activate.
* Record gameplay and use a video editor to slow it down: You can record your gameplay using Dolphin's recording feature and then slow down the footage in a video editor like Adobe Premiere Pro or DaVinci Resolve.
* Use a frame-by-frame playback feature: Dolphin's frame-by-frame playback feature allows you to examine individual frames, effectively slowing down the game. However, this is not a practical way to play the game.
Remember that these workarounds are not ideal solutions and may impact the gameplay experience.