Metal Gear Solid - Early Prototype and Beta Trailers

The early trailers of Metal Gear Solid for Playsatation.

Wikipedia: Kojima originally planned the third Metal Gear game in 1994 for the 3DO Interactive Multiplayer. Conceptual artwork by Yoji Shinkawa of the characters Solid Snake, Meryl Silverburgh, who was also a character in the adventure game Policenauts, and the FOXHOUND team, were included in the Policenauts: Pilot Disk preceding the release of the full version of the 3DO game in 1995. After the 3DO was discontinued, development shifted to the PlayStation after Policenauts was released.

The game was titled Metal Gear Solid, rather than Metal Gear 3, due to the fact that the MSX2 versions of the previous Metal Gear games were not widely released, notably Metal Gear 2: Solid Snake, which was only released in Japan and was not ported to any other platform at the time (an unrelated sequel to the first Metal Gear, titled Snake's Revenge, was released outside Japan for the NES instead, which was developed without Kojima's involvement). The word "Solid," derived from the codename of series's protagonist Solid Snake, was chosen not only to represent the fact that it was the third entry of the series, but also the transition from 2D to 3D computer graphics.

Development for Metal Gear Solid began in mid-1995 with the intention 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, the Huntington Beach SWAT team educated the creators with a demonstration of vehicles, weapons, and explosives. Weapons expert Motosada Mori was also tapped as a technical adviser in the research, which included visits to Fort Irwin and firing sessions at Stembridge Gun Rentals. Kojima 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 and mecha designs were made by artist Yoji Shinkawa based on Kojima's concepts. According to Shinkawa, Solid Snake's physique in this particular installment was based on Jean-Claude Van Damme, while his facial appearance was based on Christopher Walken. The characters were completed by polygonal artists using brush drawings and clay models by Shinkawa. Kojima wanted greater interaction with objects and the environment, such as allowing the player to hide bodies in a storage compartment. Additionally, he wanted "a full orchestra right next to the player"; a system which made modifications such as tempo and texture to the currently playing track, instead of switching to another pre-recorded track. Although these features could not be achieved, they were implemented in Metal Gear Solid 2: Sons of Liberty.

A gameplay demo of Metal Gear Solid was first revealed to the public at the 1996 Tokyo Game Show and was later shown at E3 1997 as a short video. The 1997 version had several differences, including a more controllable camera and blue-colored vision cones. It was playable for the first time at the Tokyo Game Show in 1998 and released the same year in Japan with an extensive promotional campaign. Television and magazine advertisements, in-store samples, and demo giveaways contributed to a total of $8 million in promotional costs. An estimated 12 million demos for the game were distributed in 1998.