Johnny Nero: Action Hero stars Johnny Nero in three comic-style adventures, where he destroys the evil Tarelian empire, battles undead mummies for an ancient jewel and liberates a ghost town from an evil sheriff. The game has two modes. The Standard Mode allows one or two players to each fire a lightgun and the Guns And Fury Mode which allows one player to fire both lightguns simultaneously. The player must shoot as many enemies on the screen in fast succession. A circle indicator shows enemies that on the verge of making a shot that will damage Nero.
There are health pick-ups to restore lost vitality as well as additional weapons with temporary but better firepower. Shooting the lightgun off screen reloads the ammunition. There are friendly NPCs that the player must avoid shooting. The player will have to face sub-bosses and end-bosses throughout the stages, which must be damaged quickly before they charge up their attacks. In between stages, the player will have bonus rounds requiring a number of targets to be shot in a limited time.