Metal Gear 2: Solid Snake[b] is a 1990 action-adventure stealth video game[c] developed and published by Konami for the MSX2 computer platform.

Set in 1999, a few years after the events of the original game,[d] Solid Snake must infiltrate a heavily defended territory known as Zanzibar Land to rescue a kidnapped scientist and destroy the revised "Metal Gear D".

As in the original Metal Gear, the player's objective is to infiltrate the enemy's stronghold, while avoiding detection from soldiers, cameras, infrared sensors and other surveillance devices.

Many of the weapons and equipment from the first game are brought over along with new items such as robotic mice used to distract enemies, a camouflaged mat and three different types of rations, each with special attributes.

Later versions of the game removed the password feature in favor of standardized storage media such as memory cards and internal hard disk drives.

The bosses of this installment consist of Black Color (Black Ninja in later versions), an experimental drug-enhanced ninja from a disbanded NASA project (who is revealed to be Kyle Schneider from the original Metal Gear); Running Man, a former Olympic runner turned terrorist; Red Blaster, an explosive expert from Spetsnaz; Ultra Box (the Four Horsemen in later version), an assassination squad specializing in confined spaces; Predator (Jungle Evil in later versions), a jungle warfare expert from the South African Reconnaissance Command; and Night Sight (Night Fright in later versions), an assassin from Vietnam who uses a state of the art stealth suit that renders him invisible to both radar and the human eye.

A major oil crisis seriously affects the global economy in the late 1990s, with petrol deposits running out faster than previous estimates.

To counter the problem, Czech scientist Dr. Kio Marv bio-engineers a new species of algae, OILIX, that could produce petroleum-grade hydrocarbons with little expense and effort.

He unveils the algae to the World Energy Conference in Prague and was on his way to a demonstration in the United States when he was kidnapped by soldiers from Zanzibar Land, a Central Asian country established in 1997 after a successful independence war against the Soviet Union.

FOXHOUND's new commander, Roy Campbell, brings Solid Snake out of retirement and sends him to Zanzibar Land to rescue Dr. Marv on Christmas Eve 1999.

Over the course of his mission, Snake teams up with Holly White, a CIA operative posing as a journalist, and Gustava Heffner, an StB agent and Dr. Marv's bodyguard.

Determined to finish his mission, Snake fights against Zanzibar Land's elite mercenary force and manages to reach Dr. Marv's cell.

In addition, Snake learns that Madnar volunteered his services to Zanzibar Land to finish work on Metal Gear as revenge against the scientific community shunning him after the events of the first game.

Following the success of the NES version of Metal Gear, which sold over a million units in North America, Konami began the development of a sequel for the same platform titled Snake's Revenge designed specifically for the overseas market.

After undergoing a business trip to the sales division of Konami, Kojima successfully convinced his superiors to approve the development of Metal Gear 2: Solid Snake.

[11] Originally Solid Snake was announced with a February to March 1990 release window, but was delayed to July, undergoing an increase in ROM size from 3-Megabit to 4-Megabit.

[17] The first port of Solid Snake to another platform was the Japanese feature phone version released on October 1, 2004 as a downloadable app on i-mode, EZweb, and Yahoo!

[18][19] The game's music was written by Konami Kukeiha Club members Tsuyoshi Sekito, Masahiro Ikariko, Mutsuhiko Izumi, Yuko Kurahashi, Tomoya Tomita, Kazuhiko Uehara, and Yuji Takenouchi.

Additionally, Integral features two hidden tunes based on Solid Snake available via a secret codec frequency in the main game.

They concluded that "only diehard fans will find the experience rewarding" and that the best way to play the game is through the bonus disc of Metal Gear Solid 3: Subsistence.

[24] IGN notes that Solid Snake introduced stealth mechanics such as making noise to attract guards, crouching and crawling on the ground, disarming mines, and enemies having view cones.