Appears to be a remake of XD: Gale of Darkness for a Game Boy Advanced. As if this wasn't ridiculous enough, it also features the exact same art of XD001.
EDIT: Contrary to the ignorance of the original poster, the game actually takes place on the Orange Islands, following the storyline of the anime's second season. It was created by a hacking team known as Sprihack in early 2005. However, the game ceased production after only two betas, and one of Sprihack's members, Sergio, went on to create a new game similar to Arcoiris that also took place on the Orange Islands; that game would be Pokemon Naranja.