HOW TO WALL JUMP FROM WALL TO WALL - You got to be standing at least the elevator length in this game or 3 of your characters from the wall and then you want to press the button either W, E, I, or O depending on what way you're facing/what direction the wall is then hold down the button and release it once your character direction is 80 to 70° then once your about to touch the parallel wall press the opposite button and keep doing it till you touch the roof

HOW IT WORKS FOR SINGLE WALL JUMPS - The glitch can work on any level but it only matters on the distance between the roof and the floor, the size of the platform you stand on, and the distance between you and the wall/wall to the opposite wall

MOST EFFICIENT SPOT - The best place to perform it is at the beginning of the office level where the pillar is and from where the first player spawns/last place player there in the perfect position for a speedy wall jump and all you have to do is jump backwards touch the wall jump with the opposite button and usually for me I get into the first elevator usually faster than making 2nd player move out of the way by jumping or when you're trying to get pass the Bot players.

DIFFERENTIATING BETWEEN SPEEDS - (figuring it out now will be up in under a week)

DO DIFFERENT CHARACTERS AFFECT IT - it doesn't matter what avatar you use it just matters on your position angle and height of jump to perform it.

video of me doing the glitch: https://vimeo.com/737205153

adding more info soon...

Note from @Niro69420: Wall jumping is not a technique that has too much of a use within speedruns, but it is still a very helpful trick to learn. :)