The player starts each mission with a simple handgun with infinite ammo and 10 grenades.
The game uses a standard 3-button configuration: a shoot button, a jump button and a grenade button. Later on the series, Marco and Tarma are joined by S.P.A.R.R.O.W.S agents Eri Kasamoto and Fio Germi, as Morden makes multiple allegiances with an alien race and other military groups. In the first game, the players take the role of the Regular Army's Peregrine Falcon Squad soldiers Marco Rossi and Tarma Roving, and must face the villain General Morden and his Rebel Army, who wants to eliminate the governments and establish a new order, all of this fueled by his anger caused by the death of his family that could have been prevented if the Regular Army was not corrupt. The first game was released in 1996 for the Neo Geo MVS arcade platform.
With some exceptions, the games belong to the Run 'n' gun genre - sidescroller platform games with Shoot 'Em Up elements, where the player must run through a stage while shooting at various enemies. Metal Slug is a popular video game franchise created by Nazca and now owned by SNK, who created the sequels to the original game.
