The game has three episodes, the first of which was distributed as
shareware. Each episode features three different worlds, making a total of nine levels; the only exception is the final planet of Episode 3, Proxima Seven, which has only two stages. Following the release of the shareware version, publisher 3D Realms was inundated with requests that the game be playable with a
mouse, leading the company to include a mouse option in the commercial version of the game. The original
floppy disk release was followed by a
CD-ROM version. The CD-ROM version added 70 MB of extended pre-rendered 3D
cut scenes, a bonus hidden planet, higher image resolution (including more detailed textures) and support for 8-
player network multiplay. The Macintosh port was published separately by
MacSoft. In June 2015, to celebrate the game's 20th anniversary, the game's original developer and one of the co-founders of Terminal Reality,
Mark Randel, released a version for
Android and
iOS, published by Trebuchet Entertainment. A remastered version, subtitled
Boosted Edition, was released on March 14, 2023 for Windows,
Nintendo Switch,
PlayStation 4 and
Xbox One. It adds widescreen support, upscaled graphics and extended draw distance. ==Reception==