With the help of Huey, Dewey, and Louie, Data-Sora manages to find and enter Traverse Town's Keyhole, seeking to destroy the source of the world's bugs. An energy spike limits Data-Sora's abilities, forcing him into a side-scrolling area. Data-Sora eventually manages to destroy the Guard Armor, the source of the bugs and energy spike.
Later, when Maleficent attempts to trap Data-Sora within Data-Riku's personal datascape, Data-Sora is forced to evacuate back to Hollow Bastion through a side-scrolling area, at the end of which he finds and defeats Maleficent in dragon form.
Side-scrolling stages are viewed from a 2D, side perspective and are split up into several stages. The map indicates how far away the next stage is. Data-Sora can only run, jump, glide, block, dodge roll and attack with the Keyblade. Deck commands are disabled and are replaced with overlay commands, which are obtained by picking up the diamond-shaped power-ups peppered throughout each stage.
Bug Blox block Data-Sora's path, and occasionally Blox fall from above. If he falls into a pit, Data-Sora takes damage and then respawns after a few seconds. Heartless also appear throughout the area.
In Traverse Town's side-scrolling sequence, the screen is constantly scrolling forward, pushing Data-Sora ahead if he lags behind and restricting him from going too far. Data-Sora can be crushed between a block and the moving screen, dealing damage and causing him to respawn. At some points, the screen will stay still, requiring Data-Sora to defeat certain enemies or go a particular place in order to continue.
In Hollow Bastion II, the screen follows Data-Sora; however, there is a time limit to complete the stage. In addition, Bug Blox are replaced by colored boxes. Yellow boxes are the equivalent of regular Blox and red boxes are substitutes to Danger Blox. Blue boxes are unique, in that they summon moving platforms of unbreakable blocks when broken.