Metal Slug 3 — play free online

How to start playing

Select Play now, allow the external player and press its PLAY NOW button. Wait for the game to boot, click inside the picture, then press Right Shift to add a virtual coin. After CREDIT changes, press Enter. Wait for SOLDIER SELECT, choose with the arrows and confirm with X. Let the MISSION 1 parachute entrance finish before testing movement, X to fire, Z to jump and S for a grenade. After confirming the soldier, a PLEASE WAIT countdown can appear before the mission; it is part of the arcade start sequence.

Right Shift is the key on the right side of the keyboard; coins are key presses and require no payment. If SOLDIER SELECT is still loading, wait instead of repeatedly pressing Start. A title screen or automatic demonstration is not your session. Look for your character selection, the 1UP display and a response to your own inputs. Click the picture again if keys stop responding.

Metal Slug 3 routes: choose a path, then learn it

The first four missions offer alternative routes; branches rejoin at the mission boss. Your route changes the enemies, vehicles, equipment and prisoners you encounter. Five missions does not mean five short identical stages: the final mission is a long sequence of sections rather than another set of early-stage branches.

For a first run, repeat one route and learn where an enemy appears before trying every entrance. At a fork, decide before walking into an opening; do not assume you can backtrack after the screen advances. If you change routes on a later attempt, expect a different approach to the boss and a different stock of ammunition.

Transformations change what your buttons can do

In the zombie section, infection changes the soldier into a slower form. Normal weapon upgrades and vehicles are unavailable in that state, and movement is more restricted. The grenade action becomes a powerful blood attack. Medicine restores normal form; the power of that attack is not a reason to treat the zombie as invulnerable.

Mummy and other altered states also mean that familiar movement or weapon behavior may change. Check the character animation and available attack before attempting the same jump again. Snow from a Sasquatch can immobilize the soldier, so keeping distance is more useful than assuming that firing alone solves every hazard. These later encounters were researched, not reached in our short startup check.

Weapons, grenades and prisoner rescues

X is the attack button: on foot it fires, with a close-range melee action when appropriate. Use direction to aim and move; crouch before a low opening instead of jumping blindly into incoming fire. Special weapons have limited ammunition, while the basic gun provides a fallback. Watch ARMS and BOMB on the HUD and save a few grenades for an obstructing enemy or boss opening.

Freeing a prisoner can provide an item or weapon. The end-of-mission rescue bonus depends on keeping the rescued count until the finish; dying resets that tally. Take a safe rescue rather than trading a life for an item. Compared with the first Metal Slug, route choice and changes of form or vehicle demand more than memorizing one tank-and-infantry rhythm.

Keyboard controls

Player 1 defaults from the embedded player's Controls Settings. Right Shift means the Shift key on the right of the keyboard. Click inside the game before pressing keys; remapped keys take precedence.

Devices, loading and progress

Desktop Chrome on macOS was used to check startup and keyboard input on November 2, 2026. The game runs in an external RetroGames.cc player. No app or browser plugin installation is required; game and emulator resources still download after you start.

Android phones and iPhone/iPad have not been tested on physical devices. Touch controls, simultaneous button presses, sound and fullscreen behavior are unverified. Use a desktop keyboard for the verified setup; a smaller screen alone does not establish phone compatibility.

A page favorite only bookmarks the game. Automatic progress recovery and the provider's save-state or online-play features have not been verified. Reloading can lose the current session. For missing sound, interact with the game and check its speaker control; for ignored keys, click the game again.

Fix a game that will not load · Understand browser game saves

Player questions

Version, sources and updates

Version: Metal Slug 3, SNK, 2000, Neo Geo MVS NGM-2560. The public Embed Code matches the FBNeo mslug3 set. The desktop test covered startup and short player-one combat, not all five missions. Later-route mechanics below are source-based guidance rather than a claim of a complete playthrough.

Guide maintained by WASM Arcade Directory · 2026-11-02

RetroGames.cc — Metal Slug 3 — Exact arcade version and public Embed Code checked; startup and player-input tests recorded November 2, 2026. This was a short gameplay check, not a complete playthrough.

WASM Arcade Directory is an independent guide site, separate from RetroGames.cc and the original game publishers. The embedded player's interface and game language may differ from this guide. No player totals, ratings or network multiplayer results are claimed.

• FBNeo — Metal Slug 3 NGM-2560, SNK, 2000 Neo Geo MVS set
• SNK Steam listing — original arcade missions and branching paths; port services differ
• Metal Slug Wiki — arcade branches, forms and vehicles
• Wikipedia — Metal Slug 3 arcade gameplay and prisoner scoring