However, if two exclamation marks appear over the enemy (or the player triggers an alarm by being spotted by a camera, infrared sensor or by creating a loud noise through an explosion or an unsuppressed gunshot), reinforcements from off-screen will appear as well.

If Snake is seen and only a single exclamation mark appears over an enemy's head, only the enemies in the player's present screen will attack and Snake can escape by simply moving to an adjacent screen.

The method of escaping varies depending on the circumstances behind discovery: If the player is seen, the game enters the 'Alert Mode.' In this situation, Snake must escape from enemy's sight in order to resume infiltration. The player controls a military operative codenamed Solid Snake, whose objective is to infiltrate the enemy's base while avoiding visual contact and direct confrontation with patrolling guards. Solid Snake avoiding a visual encounter with enemy soldiers (MSX2 version). The game was a major international success, with the NES version selling 1 million units in the United States. Players control Solid Snake, an operative of the special forces unit FOXHOUND, who goes on a solo infiltration mission into the fortified state of Outer Heaven to destroy Metal Gear, a bipedal walking tank capable of launching nuclear missiles from anywhere in the world, as well as rescue a number of fellow agents who have been captured by the enemy. The MSX version was also released for Wii Virtual Console and PC. A more faithful port of the MSX2 version was later included in Metal Gear Solid 3: Subsistence for the PlayStation 2, as well as in the HD Edition of the same game released for the PlayStation 3, Xbox 360 and PlayStation Vita, with these newer ports featuring a revised translation and additional gameplay features.

An emulated Famicom version came with the special edition of Metal Gear Solid: The Twin Snakes on GameCube. A reworked port of the game was released for the Famicom a few months later, which later saw release in international markets for the NES over the following two years this version was developed without Kojima's involvement and features drastically altered level designs, among other changes.

Considered the game to popularize the stealth game genre, it was the first video game to be fully developed by Hideo Kojima, who would go on to direct most of the games in the Metal Gear series. Metal Gear is an overhead military action-adventure video game originally released in 1987 by Konami for the MSX2 computer in Japan and parts of Europe.

Metal gear rising ost here i come