Battlezone and Battlezone II are not the only games under the Battlezone name; Activision licensed their name from Atari, who have created several games under it both before and since.
Battlezone (Arcade)
The original game of its name, Battlezone was a vector-based wireframe tank game in which players were required to destroy other tanks and flying saucers. It became notable as one of the first games to use a 3D perspective, and its realism was such that a version of it was commissioned by the United States military to train soldiers to use Bradley tanks. It was this version of Battlezone which provided the original inspiration for Activision's series, with the flying saucers analogous to the Furies.
Battlezone 2000
Battlezone 2000 is a deluxe port of the original game released for the Atari Lynx in 1995. Atari and Hand Made Software had originally planned to create a much larger and more immersive game using a completely different sprite graphics system, but testers deemed it too complex and it was replaced with a port more true to the original's gameplay and vector graphics. This seperate part of the game is still accessible through a cheat code and is completely playable, though almost entirely undocumented.[1]
Battlezone (PSP)
In 2006, Atari rebooted Battlezone with a arena deathmatch PSP game. It has some design similarities to the Battlezone series, such as hovertanks, but is completely unrelated.
Battlezone (XBLA)
In 2008 Atari again rebooted the game, this time commissioning Stainless Games to produce a remake of the original. It features both a vector version similar to the original and a 3D rendered version.
Battlezone (Rebellion)
After winning the Battlezone name at auction following Atari's bankruptcy, Rebellion Developments announced a new version of the arcade Battlezone at E3 2015. This new version of the game targeted VR devices, particularly the Sony Morpheus, and aims for a PC and Playstation 3 release.