DOOM

It emerged from a 3D game engine developed by John Carmack, who wanted to create a science fiction game inspired by Dungeons & Dragons and the films Evil Dead II and Aliens. The player controls an unnamed space marine—later termed "Doomguy"—through a series of levels set in military bases on the moons of Mars and in hell. While the environment is presented in a 3D perspective, the enemies and objects are instead 2D sprites presented from several preset viewing angles, a technique sometimes referred to as 2.5D graphics or billboarding. While traversing the levels, the player must fight a variety of enemies, including demons and possessed undead humans, while managing supplies of ammunition, health, and armor. Enemies often appear in large groups, and the game features five difficulty levels which adjust the quantity and damage done by enemies, with enemies moving faster than normal on the hardest difficulty setting. The player can find weapons and ammunition throughout the levels or can collect them from dead enemies, including a pistol, a chainsaw, a plasma rifle, and the BFG 9000.Power-ups include health or armor points, a mapping computer, partial invisibility, a radiation suit against toxic waste, invulnerability, or a super-strong melee berserker status. Two multiplayer modes are playable over a network: cooperative, in which two to four players team up to complete the main campaign, and deathmatch, in which two to four players compete to kill the other players' characters as many times as possible. Multiplayer was initially only playable over local networks, but a four-player online multiplayer mode was made available one year after launch through the DWANGO service. Doom is divided into three episodes: "Knee-Deep in the Dead", "The Shores of Hell", and "Inferno". The campaign contains very few plot elements, with the minimal story instead given in the instruction manual and in short text segues between episodes. In the future, an unnamed marine is posted to a dead-end assignment on Mars after assaulting a superior officer who ordered his unit to fire on civilians. With no way off the moon, and armed with only a pistol, he enters the base intent on revenge. In "Knee-Deep in the Dead", the marine fights demons and possessed humans in the military and waste processing facilities on Phobos. The episode ends with the marine defeating two powerful Barons of Hell guarding a teleporter to the Deimos base.