Play Metroid Fusion Debug Online

Metroid Fusion Debug is an unreleased version of the Game Boy Advance title Metroid Fusion, developed by Nintendo R&D1 and published by Nintendo. It exists as a prototype from the early 2000s, a period when the GBA was establishing itself with a strong lineup of action and adventure games. This particular build offers a glimpse into the game's development before its final commercial form.

You control Samus Aran as she navigates the isolated environments of a biological research station. Your primary objective is to survive and uncover the source of a parasitic threat known as the X. The gameplay is built on screen by screen exploration, where you use your arm cannon to fight hostile creatures and absorb their cores to regain health and missiles. A key mechanic involves the SA-X, an invincible doppelganger that stalks you through the station, forcing you to hide or flee during its appearances. The pacing is tense, with quiet moments of backtracking suddenly interrupted by these high stakes chases. Navigating the station's interconnected map and managing your limited resources creates a consistent, challenging pressure. Playing it feels like moving through a carefully constructed, hostile ecosystem where every new corridor could hide a threat.