Jet Force Gemini - Development

Development

Development of Jet Force Gemini began in 1997 by Rare's Blast Corps team, with lead programmer Paul Mountain, who had previously worked on Diddy Kong Racing. The inspirations of the game were manifold. The free-roaming nature of Nintendo's Super Mario 64 influenced the scale and the openness of some of the backgrounds and settings, and the collecting and upgrading of weapons were inspired by Super Metroid. Additionally, 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... we were inspired by all the good stuff we'd played and enjoyed playing". The game also borrowed from other non-related video games 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."

At one time, the game's protagonists Juno and Vela were designed as younger and more cartoon-like with large heads, but were later changed to their more mature versions at Nintendo's behest. The game's controls were one of the main concerns during development. The idea was to retain a character-based game, where players could see the character they were playing, while keeping the tightness and accuracy of first-person shooters. Rare initially attempted to automate the change of view and targeting mode based on the context of the action, but this idea was eventually replaced with a manual system. According to Mountain, "The solution we ended with is a beautiful thing... It feels very old-school to me; difficult, unforgiving, but ultimately precise". As several members of the team enjoyed racing games and had also worked on Diddy Kong Racing, the team decided to include the futuristic Ant racing featured in the campaign and the top-down arcade racing games in the multiplayer.

Developers initially considered the possibility to use the 4MB N64 Expansion Pak, though the idea was eventually dropped. According to Mountain: "We wanted to deliver the same experience to all players and were confident that we could do this using the standard 4MB of RAM on the console." This led to some confusion as the box cover for the original release stated that it did support such a feature. Nintendo provided a quick-fix to the mislabeled covers by providing stickers declaring its rumble pak compatibility and fixed later printings of the boxes. The game was originally planned for release on August 31, 1999, but was pushed back to September 27 in order to give the programmers time to polish up the game. It was then pushed back even further to October 11 due to manufacturing delays. Jet Force Gemini was localized as Star Twins (スターツインズ?) in Japan due to Nintendo's opinion that the Japanese pronunciation of the original name, "Jetto Fōsu Jeminai" was too difficult to pronounce. 4Kids Entertainment obtained the rights to merchandising both Jet Force Gemini and Perfect Dark toys, movies, and other recreational products, although 4Kids did not go on to produce any merchandise for the franchise.

In 2006, an unreleased Game Boy Color version of Jet Force Gemini was discovered via Assembler Forum. The current owner of the prototype cartridge has attested that the game appears to be nearly complete, though it was never officially announced by either Rare or Nintendo. In an October 2012 interview, Ex-Rare designer and producer Martin Wakeley said, "Jet Force Gemini on the Gameboy 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."