METAL SLUG 3 on Windows: Arcade Mode, Branching Paths, Mission Mode, and Online Co-Op

Arcade Mode: Five Stages, Branches and Giant Bosses

Arcade Mode, also called the Main Mission, starts the arcade version of the game from its opening. It spans five large stages, each described as immense and challenging. These stages contain multiple branching paths, so the player can enter different areas instead of following a single fixed route. The mode is the main campaign, and its progress is tied to clearing those five stages. No additional rules for continues, scoring, or stage transitions are documented in the supplied material.

The branching paths are part of the stage layout: each of the five stages offers multiple routes into new areas. The documented goal is to explore those areas while advancing through the arcade version from the beginning. The same five-stage structure is repeated across the mode descriptions, linking the main mission to the branching layout rather than to a separate stage-select system. The source does not assign specific route names, boss encounters, or route-specific rewards, so only the five-stage count and branching structure are confirmed.

Mission Mode: Unlocked Stage Select and Solo or Shared Training

Mission Mode, also labeled Stage Select, changes how the player reaches the action. Instead of starting from the arcade opening as in the Main Mission, the player picks from the stages already unlocked. The selection is limited to missions unlocked so far, so the mode works as a replay and practice space for cleared or opened content rather than a way to jump ahead. Favorite stages can be played at will, giving direct access to any available mission without replaying the five-stage campaign from its first screen.

Within Mission Mode, training can be done alone or with a brother-in-arms, meaning a second player can share the selected missions. The shared training uses the same unlocked-stage pool, so both participants work on missions that have been opened. This differs from the Online Mission option, which connects to Steam to clear missions with distant friends through Online Co-Op Play. Mission Mode itself is the local stage-select and training layer: the player chooses an available mission, then trains solo or alongside a partner on it.

Online Co-Op Play Through Steam

Online Co-Op Play is the game's network layer, reached through a mode labeled Online Mission and Online Multiplayer. The documented setup is a Steam connection, made so that a player can clear missions together with friends who are far away rather than seated at the same machine. The stated objective of the mode is clearing missions, matching the goal already attached to the campaign and stage-select content. The source also invites pairing with a fellow countryman or a foreign ally before the mission begins, framing the partner search as the step preceding play.

Within Online Co-Op Play the concrete actions are connecting to Steam, finding a partner, and then clearing missions together; the source presents the partner as someone distant, whether from the same country or elsewhere. This separates online play from the stage-select training covered elsewhere, whose shared play is described without a Steam connection or distant friends. The documented rule interaction is therefore simple: Steam provides the link, the two players form a pair, and mission clearing is the shared goal once the mission starts. No further online rules are supplied beyond those steps.

Leaderboards, Gallery and Configurable Controls

Leaderboards give players a way to check their current rank and score at any time, and the stated goal is to compete with other players to become the world's number one soldier. A separate Gallery section holds original illustrations that must be unlocked before they can be viewed, so the gallery fills as the player opens its entries. These two sections sit apart from the action modes, one tracking standing against other players and the other presenting artwork collected through play.

The Settings section is where display, control, and language options are configured. Its control portion is the place where the game's controls are set up, matching the profile's description of the game as having simple and intuitive game controls. Display settings govern how the game is shown, and language settings choose the text language, all handled from within the same configuration area rather than emerging from the stages or missions themselves.

First published Oct 28, 2026.