Wall jumping can be performed on two types of terrain scattered throughout I Wanna Be The Guy: ivy vines and power jump walls. The former, more natural-looking obstacle of the two is found most commonly on the Path to Kraidgief's Hideout. Power jump walls, which resemble black-striped yellow caution tape are found primarily within and around Guy Industries Tower. Both are slick surfaces that will inevitably be released if the action to jump off is not taken by the player.
Throughout his quest to become The Guy, The Kid is required to scale and repel off of both wall surfaces to avoid spikes, delicious fruit, and various other hazards, and/or to reach higher ledges. The mechanics for scaling and repelling off of both types of wall are similar yet slightly different. In TenShots' speed run of the game this was admitted to be a programming error on the part of the game's designer, Michael "Kayin" O'Reilly.
Ivy walls are easily scaled by simply pressing- not holding down- the shift key when repelling, and quickly facing back toward where The Kid just jumped from and holding that directional key down which, if done correctly, places him slightly higher along the vine. This process can be repeated as many times as necessary until the desired height is reached.
Power jump walls require incredible precision to scale in locations where scaling them is even possible at all. Rather than relying on a single wall as is the case with vine walls, power jump walls can only be scaled if two are facing each other in close proximity. If this condition is met, The Kid can repel off one wall, facing toward the other and cling to it to end up significantly higher than when he first jumped.
When repelling off of ivy vine-covered walls, The Kid will jump significantly farther if the shift key is held down as opposed to simply pressed. When on power jump walls, The Kid will jump about as far regardless of whether or not the shift key is held down while jumping. The difference is he will jump higher if the key is held rather than pressed. Knowing when or when not to hold is crucial to advance to certain areas and to obtain secret items #4 and 5.