Metroid Fusion, also known as 'Metroid 4', is an action-adventure game released for the Game Boy Advance in 2002. Developed by Nintendo Research & Development 1 and published by Nintendo, it is the fourth installment in the Metroid series. Players control Samus Aran, a bounty hunter who investigates a space station invaded by organisms known as X parasites. The game introduces new gameplay elements, such as the ability to absorb enemies to regain health and ammunition. The game features exploration, platforming, and puzzle-solving elements, as well as a unique art style that differentiates it from its predecessors.