Hovertank One (also known as Hovertank and Hovertank 3D) is a vehicular combat game for MS-DOS developed by id Software and published by Softdisk in April 1991. A similar engine was used by MIDI Maze for the Atari ST in 1987, as well as Wayout for the Apple II from 1982 and The Eidolon from 1985 for the Atari 8-bit computers.
The source code to the game, owned by Flat Rock Software, was released in June 2014 under GNU GPL-2.0-or-later.