Vexx himself went through numerous changes, starting as a creature by the name of Jinx, who possessed magical gloves inspired by the Battle Chasers comic book series. This was changed to a rodent-like creature named Clip who had a small, reptilian sidekick named Mischief, but their similarities with the Jak and Daxter concept convinced the developers to change the main characters once again, ditching mischief in favor of a platformer based around one central protagonist.
Five different new characters had been designed, with at least two of them being combined into Vexx's current look. He was then named Jinxed and was at one point a female, but he was renamed to Vexx and changed to male.
An old render of the main cast shows Yabu with greener skin and spine-like hair, Reia with tan skin and different colored clothes, and Darby, who doesn't appear to be affected by blindness and has more detailed facial hair, surrounding Vexx who back then, was still known as Jinxed.
In the game's official strategy guide, there exist three unused enemies: Moddax (dog-reptilian enemies), Fuegore (an insect enemy), and Stingers (giant, flying Shadowcreep heads). In both the game guide and the manual, Puggles have a different daytime version, showing them as more beady-eyed with no horns. However, the game guide could be based on a near-final build of the game that was left unedited.
Vexx originally had 18 levels split into 6 worlds, with them being connected together and visible from a distance, all surrounding the Central Landspire. The cut levels included: Vexx's home village of Overwood, The Temple of Nanyk, Talon's Maw, Undertow Tower, Submarilis, Devil's Well, Pyroseum, Sorrow's End, and Mirrorrim.
In several previews, Overwood was originally named Rockhaven, but the music files give it the name Redwood. Some early press releases also mention that Vexx was going to try and reach Landspire to confront Yabu. Along with this, Reia tells Vexx during the central cutscene that he has to "activate the three outer structures of Astara," hinting at a plot point removed late in development.
Beta screenshots show the early layout of the levels, worlds that can be seen in the backgrounds, enemies in different areas, different collectibles, a bar-based health meter, and possibly darker lighting to the game, as well as more vibrant and colorful textures in various areas.
A concept by Manuel Carrasco for the canned Vexx 2, showing what appears to be a dark version of Vexx. A Vexx 2 logo can be seen on the bottom left.
A concept for darker War Talons in the sequel by Manuel Carrasco.
An early Vexx 2 concept by Kynan Pearson. It shows a super-powered version of Vexx with a summoned spiritual creature behind him. Kynan Pearson had envisioned these creatures as new powers Vexx would've gained in the sequel. The creatures were inspired by the summon abilities from the anime JoJo's Bizarre Adventure.