Unsourced material may be challenged and removed. Combat and movement are turn-based, allowing the player time to select their responses in combat. The player turns at 90 through the breach rpg pdf download angles and moves space by space.

Many features of the original are retained, including the status bar face, sound effects and the majority of the weapons and monsters. Notably absent are the Chainsaw, Arachnotrons and Spider Mastermind. A difference from the original is that each monster is one of three levels of difficulty, and is colored to indicate this. The game also adds several new elements. The game is divided into section based on Sectors in the base.

The Junction is the staging area or main town for the game. Guerard was not on good terms with Jensen. Three weeks prior to the start of the game, Guerard asked Graff to perform a security audit on Jensen. Jensen failed the security audit and was dismissed for this security breach. Jensen suspected that Guerard was involved in his dismissal.

During the same time, demons started to invade the installation, appearing out of nowhere. It is around this time that the game begins. Early on in the game, the Marine meets Dr. Jensen when he was accessing a computer terminal investigating his dismissal. During the exploration of first few sectors of the installation, the Marine receives help from Dr. Guerard in gaining access to various locked down areas. In Biological Research Facility, the Marine meets Dr.