A 3D space combat simulator, BattleSphere's story was based upon an episode in the original Star Trek television series and it plays similarly to Star Raiders.
Seven alien races vie against each other - the victor will control the galaxy. They meet in an arena in Sector 51, a spherical sector of space formerly used by the Earth government to secretly test new weapons and starships. Gameplay consists of 5 different play modes with different scenarios and goals. Choose from various starships (each with unique weapons systems) and battle the aliens, who have also chosen their best fighters and have many space ships of their own.
BattleSphere was developed by three people in their spare time over a period of five years. The team encountered many hurtles including lack of support from Atari and legal battles with JTS and Hasbro, not to mention actually producing the carts long after the standard production channels had disappeared.
A single pre-release cartridge of BattleSphere, signed by the developers, was sold for $US 1,575 via eBay on March 6, 2000 - the official distribution of the game started after the auction was over. The proceeds from the auction were donated for diabetes research. A copy of the eBay auction page can be viewed here.
BattleSphere takes place on a enclosed region in space named Sector 51, which is a clear reference to Area 51. In the game, the sector was an ancient alien testing ground for weapons by the Smg'Heed race.