A new system was implemented with Metal Slug 6 allowing players to carry and switch between the handgun and two other weapons. Similarly, when ammunition runs out, the player reverts to using the handgun, which has unlimited ammunition. When a new weapon is found, it replaces the previous one. The player can only use one weapon at a time.

The player starts with only a simple semi-automatic handgun ( Metal Slug 6 and 7 used a fully automatic handgun in place of the stock semi-auto first used in every game including a spin-off) as the game progresses, the player may pick up new weapons. This leads to the player's ability to run in and use melee attacks to take down a number of enemies at once, as well as the ability to quickly defeat enemies that can take plenty of damage, such as the mummies in Metal Slug 2. The player's melee attack is also much stronger than most shots. 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. In most run and guns, contact with an enemy leads to damage. The run and gun pit a player against many enemies with extremely powerful weapons pick-ups. The gameplay consists of run and gun elements as well as in later releases shoot 'em-up, mechanics. Gameplay Metal Slug machine in the Musée Mécanique, San Francisco The games focus on the Peregrine Falcon Squad, a small group of soldiers who fight against a rebel army, aliens, zombies, mummies and various other forces intent on world domination. Originally created for Neo-Geo arcade machines hardware (MVS) and the Neo-Geo home game consoles (AES) hardware, the original games have also been ported to other consoles and mobile platforms throughout the years, with several later games created for various other platforms. Spin-off games include a third-person shooter to commemorate the 10th anniversary of the series and a tower defense game for the mobile platform. Metal Slug ( Japanese: メタルスラッグ, Hepburn: Metaru Suraggu) is a Japanese multimedia franchise and run and gun video game series originally created by Nazca Corporation before merging with SNK in 1996 after the completion of the first game in the series.

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