In the PC version, you can butt bounce on spectral portals and on certain boxes, while in any other version you can't. Most skips are still possible on GameCube despite that, though.

If you want to learn the game, I'd suggest watching the WR vid and asking questions in the Pac-Man Discord server (https://discord.gg/hRWw4pr). I can answer any questions you might have and explain all the tricks.