鋼嵐-メタルストーム is a free-to-play mecha battle RPG set in a futuristic world where players can customize their 'ST' mechs extensively. The game is set on a newly formed island, Mihama, where a new element called 'Sierra Element' enhances mech performance. Players take on the role of commanders, directing their pilots with various jobs like snipers and mechanics to devise strategies for victory. The game emphasizes tactical decision-making, allowing players to choose between aggressive and cautious approaches during combat.

The game features extensive customization options, letting players paint and decorate their mechs, creating unique designs. Players can strategically target and destroy specific mech parts to hinder enemy movement or weapon use, adding depth to battles. With a rich storyline involving intriguing characters and secrets of Mihama Island, players are drawn into a narrative filled with twists and motivations, enhancing the overall gameplay experience.