Set in the year 2044, players assume the role of a recently recruited Space Hound by DEFCON to take control of the Perseus space fighter in a battle to defend Earth and counterattack the invading forces of the Morphon alien race, who wants to reach the planet and destroy the human race after picking up signal of the Europa III satellite and destroying it as a result.

Zero-5 is a shooter game that is primarily played in a first-person perspective, where the player assume the role of a recruited Space Hound pilot by DEFCON to take control of the Perseus space fighter in a battle to defend Earth from the invading forces of the Morphon alien race, who are set to eradicate the human race after their signal was picked up signal by the now-destroyed Europa III satellite across 16 missions, each one featuring a different scenario and circumstances to complete in order to progress further, with later missions increasing in difficulty.

If the game is played on an Atari ST machine that does not have more than 1MB of memory, features such as speech synthesis and other graphical effects are deactivated.

[8] STart Micro's Arnaud Pignard compared the game with Cybermorph but highly praised its realization, audiovisual presentation, playability and longevity.

[9] ST Format's Simon Forrester also compared the title with Carrier Command, praising its fast-pacing and structured mission variety but criticized the lack of additional weapons and ability to slowdown, as well as the constant disk swapping if players did not have more than one disk drive to be used when playing.