Jet Force Gemini

Jet Force Gemini is a third-person shooter with shoot 'em up and action-adventure elements, in which the player controls the player character from a third-person perspective in a 3D environment. The game places strong emphasis on shooting large numbers of enemies while dodging their attacks. Weapons have no magazine restrictions and include grenades, a pistol, a machine gun, a sniper rifle, a flamethrower, and rocket launchers, among others. Although much of the game is spent in battle, the player has the ability to jump, hang from ledges, swim, and fly using jet packs, when needed.

In combat, the player is free to set on a manual aiming system with the targeting camera fixed behind the character's head. When using this technique, a crosshair appears on screen and the player character becomes translucent so that players can aim and shoot with finesse. By contrast, when walking around, the game plays similar to a 3D platformer.

Jet Force Gemini revolves around the galactic law enforcement team Jet Force Gemini, composed of twin siblings Juno and Vela and their wardog mascot Lupus. The game begins with the three characters in orbit around the planet Goldwood after barely escaping the destruction of the entire Jet Force fleet at the hands of the insectoid Mizar, who has been capturing and enslaving the native Tribals on Goldwood. When their ship is boarded by several of Mizar's drones, the three decide to abandon their ship and go off on their own separate paths to stop the invasion. Along the way, Juno finds and reconstructs Floyd, a small floating robot who defects from Mizar and agrees to aid the team.

After traversing various planets, the heroes find themselves reunited at Mizar's Palace and confront Mizar, who escapes to a nearby asteroid and sets course to impact with Earth. To help the heroes, the Tribals' leader King Jeff provides them with an ancient starship that can quickly catch up to Mizar's asteroid, asking them to rescue all the Tribals throughout the galaxy in exchange.

Jet Force Gemini was developed by Rare's Blast Corps team. Work on the game began in 1997 with lead engineer Paul Mountain, who had previously worked on Diddy Kong Racing. The inspirations of the game ranged from 80s arcade classics to more recent titles of the time. The free-roaming nature of Nintendo's Super Mario 64 influenced the scale and the openness of some of the backgrounds and settings, while the collecting and upgrading of weapons were inspired by Super Metroid.

Mountain revealed that "the behaviour of the bad guys was a mixture of arcade space shooter formations and Quake-style 'attack and cover' mechanics". According to him, "I suppose, in short, we were inspired by all the good stuff we'd played and enjoyed playing." Jet Force Gemini borrowed elements from non-video game sources. Lead artist Lee Musgrave admitted, "There are elements of Star Wars in there, Aliens, Dune, Battle of the Planets, even Stargate – it was a real mix of everything and anything 'space' related."

Jet Force Gemini received generally positive reviews from critics. Edge described it as "a straightforward blaster at heart", while AllGame claimed that it "pays homage to 8- and 16-bit games with its emphasis on high-intensity action and level design that requires skill with the controller." Writing for IGN, journalist Matt Casamassina remarked that, although Jet Force Gemini has some flaws and could be more polished, it is "still one of Nintendo 64's most original games and it has much more good going for it than it does bad." In a mixed review, Next Generation felt that the game was bloated with too many features and that it may exhaust players before it is over, concluding that the game would have been "twice as good" if "Rare had cut all the tedious parts".

The game's graphics and surround sound effects were received very positively. Casamassina described its sound effects as "dead-on and crystal clear" and its soundtrack as "some of the very best ever put into a Nintendo 64 game", while GameRevolution said that the game "goes for a more operatic feel than the generic video game techno." Graphically, the game was highlighted for its "visually stunning" settings, "state-of-the-art" animations, and special lighting, with Game Informer remarking that the game's "enormous" explosions help intensify the action. Despite the praise, some critics observed occasional frame rate drops when the action increases or when the game is played in non-widescreen mode. Edge also criticized the camera for refusing to move in some situations, requiring players to enter the aiming mode to manually center it behind the player character.

After the release of Jet Force Gemini, work on a Game Boy Color version of the game started, but the project was ultimately cancelled. According to former Rare designer and producer Martin Wakeley, Jet Force Gemini on the Game Boy Color "was the only occasion I can remember Rare outsourcing anything. It was being done by Bits Studios and was nearly done last time I saw it, I'm not sure what happened to it." The game would be a shooter played from an isometric perspective and would follow Juno and Lupus searching for Vela after a signal is broadcast from an unknown planet. The game was never officially announced by either Rare or Nintendo.

In 2000, Jet Force Gemini was ranked by IGN at number 20 in their list of The Top 25 N64 Games of All Time. In 2009, Official Nintendo Magazine ranked it the 93rd best game available on Nintendo platforms. The staff called it Rare's "big hope" due to the highly anticipated but delayed Nintendo 64 game Perfect Dark. Subsequent games developed by Rare have featured cameo appearances of Jet Force Gemini, including Kameo, Viva Piñata: Trouble in Paradise, and Banjo-Tooie.