Dennou Senki Net Merc (電脳戦記ネットマーク) is an arcade game developed by Sega with assistance from UK-based Virtuality. It is the only game created for the Sega Net Merc (セガ ネットマーク) system (a Sega Model 1 arcade board adapted for virtual reality), so the two are often used interchangably. Dennou Senki Net Merc is an on-rails shoot-'em-up game, in which players use a large gun controller to fire at enemies. Being a virtual reality game, players are also given a VR headset (a "MVD" or "Mega Visor Display", similar to those found in the VR-1), allowing for their head movements to be tracked in real time and therefore see a full 360 degree view of their surroundings. Players are always stood facing in one direction behind the gun controller during gameplay. The complex nature of the system means that a member of staff was usually on hand to assist users with the headset. The Sega Net Merc system consists of a Mega Visor Display being attached to a 3SPACE ISOTRAK II head and motion tracker and a specialised cabinet.