"Development for Metal Gear Solid began in 1995 with the intent of creating the "best PlayStation game ever." Developers aimed for accuracy and realism while making the game enjoyable and tense. In the early stages of development, a SWAT team educated the creators with a demonstration of vehicles, weapons and explosives. Hideo Kojima, the director, stated that "if the player isn't tricked into believing that the world is real, then there's no point in making the game". To fulfill this, adjustments were made to every detail, such as individually designed desks.
The characters of Metal Gear Solid were created by Hideo Kojima; modifications and mechanics were made by conceptual artist Yoji Shinkawa. The characters were completed by polygonal artists using pencil drawings and clay models by Shinkawa.
Despite being the third Metal Gear title (not including the non-canonical Snake's Revenge), Kojima chose the name Metal Gear Solid over Metal Gear 3 due to the relative obscurity of the first two games. The word Solid refers to the game being the third installment in the series, and also because the game uses 3D computer graphics. The subsequent sequels in the series also bear the Metal Gear Solid title, following a new numeral progression.
Metal Gear Solid was revealed to the public at the E3 gaming event in 1997 as a short video. It was later playable for the first time at the Tokyo Game Show in 1998 and officially released the same year in Japan with an extensive promotional campaign. Television and magazine advertisements, in-store samples, and demo give-aways contributed to a total of US$8 million in promotional costs. An estimated 12 million demos for the game were distributed during 1998." - wikipedia