Side-scrolling action platformer where you hunt down and eliminate every Metroid on their home planet. You explore a sprawling underground labyrinth, tracking 39 Metroids through interconnected caverns and ruins. Combat evolves as Metroids mature through distinct life stages, each requiring different tactics. You'll find upgrades that expand your movement options—Spider Ball lets you cling to walls and ceilings—and firepower, including the Plasma Beam. Progress is gated by Metroid kills: eliminating them in each zone drains lava or acid, opening paths deeper. No map system means you're navigating by memory and environmental cues. The structure is more linear than later entries, but backtracking still matters when you unlock new gear. Fits players comfortable with methodical exploration and pattern-based boss encounters.
