Based on the Tom Clancy novel of the same name, the game follows Rainbow, a top secret international counterterrorist organization, and the conspiracy they unravel as they handle a seemingly random spike in terrorism.

The game features realistic gameplay factors, weapon lethality, and consequences for failure, forcing players to plan their approach carefully and promoting replayability for more streamlined completion.

For most releases, praise was directed toward gameplay, multiplayer, immersion, and the game's combination of strategy and action, while criticism mainly centered on AI issues, glitches, and the graphics and controls of some ports.

Players are encouraged to find their own ways to complete objectives using a variety of tactics and methods, ranging from stealthy infiltration to a frontal assault (except in missions where stealth is mandatory).

In the planning stage, the player is shown a map of the area of operations to set team orders, such as AI pathing, team "go" codes to hold until ordered, where AI operatives will deploy equipment such as flashbangs or door breaching charges, and rules of engagement; alternatively, the player can skip this by choosing to follow a preset plan instead.

The PlayStation port was developed by Rebellion and features visible weapons in first person, entirely new mission layouts, and a smaller team size (4, opposed to 8 in other versions).

[16] Rainbow's operations against Phoenix are assisted by John Brightling, chairman of the powerful biotechnology corporation Horizon Inc., whose facilities are frequently targeted by Phoenix; Anne Lang, the Science Advisor to the President of the United States and an acquaintance of Brightling; and Catherine Winston, a biological expert working with Horizon who is rescued by Rainbow following an attack in the Democratic Republic of the Congo.

Global Security's personnel, led by William Hendrickson, will then release Brahma at the Olympics through Stadium Australia's cooling system, spreading the virus worldwide when the athletes and spectators return home.

[16] After gathering intelligence and rescuing Winston from a last-ditch attempt to silence her, Rainbow apprehends Lang and Hendrickson and prevents Brahma's release at the Olympic Village, foiling Brightling's plans.

We also knew that we wanted it to be an action game with a strong strategic component — a realistic shooter that would be fun to play even without a Quake player's twitch reflexes.

Many developers slept in a spare room of the office, Upton's mental health deteriorated to the point that he had a nervous breakdown that prompted company restructuring to reduce his workload, and network programmer Dave Weinstein (hired as part of the aforementioned company restructuring) was once stopped by police on suspicion of driving under the influence due to his severe exhaustion from crunch.

[17][18] Clancy would insist the developers add features his experts claimed were realistic, such as the fictional heartbeat sensor used in the novel that functions as a radar-like equipment item in-game.

[18] In November 1997, the developers realized the game was becoming too demanding, only having single-digit frame rates on high-end devices, so a massive two-month overhaul was ordered.

[17] Despite these setbacks, development managed to progress relatively smoothly overall, and a gameplay demonstration at E3 1998 that unintentionally displayed AI teammates rescuing hostages by themselves boosted the game's publicity ahead of release.

[44] The expansion was packaged with the original game as Tom Clancy's Rainbow Six: Gold Pack Edition when it was released in 1999 in North America in June and in the United Kingdom in September.

The game's difficulty and playstyle differences to contemporary shooters such as Quake II and GoldenEye 007 were highlighted by multiple reviewers, as was the detailed planning stage.

Trent C. Ward, reviewing the PC version for IGN, praised the complexities of the planning stage, realistic damage, competent AI, and freedom to complete missions from multiple approaches, saying it was "unlike any first-person shooter yet made.

"[78] Jeremy Dunham of IGN, reviewing the Dreamcast port, praised the game's change in pace, saying, "Long exposed to mindless romps and pointless first-person gore-fest clones, the ability to actually think and THEN destroy puts a big ol' smile on my face.

"[8] Push Square's Sam Brooke, reviewing the PlayStation port in a 2018 retrospective, enjoyed the sense of accomplishment from completing challenging missions properly, calling it "a trailblazer in its genre".

"[7] Christian Nutt, reviewing the Nintendo 64 port for GameSpot, said of Rainbow Six, "realism is the order of the day ... this game does deliver a military simulation on a very personal level.

[7] PC Gamer US favorably described the multiplayer functionality as "tense and exciting", but suggested the quick time-to-kill could make smaller matches simple and boring.

Aaron Boulding of IGN said the only issue with the port was the shortened campaign,[20] but Nutt considered the short length to be acceptable, viewing the multiple difficulty levels and the co-op mode as making up for it.

[10] Electronic Gaming Monthly highlighted the port's detailed graphics yet smooth framerate as impressive for the Nintendo 64, especially without having to resort to render fog.

[77] Nutt lambasted it as "awkward" and "aesthetically bankrupt", noting its apparent abandonment of the team leadership aspect, deeming it "an uninspired FPS with some weird hostage-saving minigame tacked on.

"[70] IGN's Matt White criticized its unusually poor graphics, and called it "a mighty fine example for impressionable young developers of how not to handle a port.

IGN's Craig Harris criticized it for removing risk factors such as enemy effectiveness and crossfire, thus making most planning and tactics worthless, though he commended Crawfish Interactive's ambition in adapting a three-dimensional shooter to a two-dimensional handheld.

[9] Frank Provo of GameSpot criticized AI issues, gameplay repetition, and noticeable reuse of sprites and sounds, but still considered it a faithful version for what it was.

[11] Dunham had the same criticisms, noting these issues still existed in the final release despite an eight-month delay in the port's development, but nonetheless deemed it "one of the deepest, most realistic games to inhabit the Dreamcast so far.

"[8] Mike Lohrey of IGN reviewed the Eagle Watch expansion, praising its new levels and additions but criticizing AI awareness issues and inconsistent damage mechanics compared to the original game.

[84] The PC version's Gold Edition release sold another 321,340 copies in the United States during 1999, and was the country's 12th best-selling computer game that year.