Metal Slug (Japanese: メタルスラッグ Hepburn: Metaru Suraggu) is a series primarily of run and gun video games created by SNK. Spin-off games include a third-person shooter and a tower defense game. Originally created for Neo-Geo arcade machines and game consoles, the original games have also been ported to other consoles, with several later games created for various other platforms. The games focus on the Peregrine Falcon Squad, a small group of soldiers who fight against a rebel army, aliens and various other forces intent on world domination.
The gameplay of the series is characteristic of run and gun games: large numbers of enemies and a player character with extremely powerful weapons. In most run and guns, contact with an enemy leads to annihilation. In this series, however, contact results in the opportunity to perform a melee attack and the opportunity for the enemy to perform a melee attack of his own, if he has one. The player’s melee attack is also much stronger than most shots. This leads to the players ability to run in and use melee attacks to take down a number of enemies, and the ability to quickly defeat enemies that can take plenty of damage, such as the mummies in Metal Slug 2.
The player starts with only a simple handgun; as the game progresses, the player may pick up new weapons. The player can only use one weapon at a time. When a new weapon is found, it replaces the previous one. Similarly, when ammunition runs out, the player reverts to using the handgun, which has unlimited ammunition. A new system was implemented with Metal Slug 6 allowing players to carry and switch between the handgun and two other weapons. The player is also equipped with grenades which can be used to throw at enemies and cause more damage, however the number of grenades is limited and must be replenished periodically with ammunition found along the way.