Doom II

The Super Shotgun in use

Doom II was not dramatically different from its predecessor. There were no major technological developments, graphical improvements, or substantial gameplay changes. Instead, the development team took advantage of advances in computer hardware since the release of the original game that allowed them to do more with their game engine by making much larger and more intricate levels. The game still consists of the player navigating large nonlinear levels. Each level is infested with demons that can be killed with a variety of weapons that can be picked up throughout the game. Levels are completed by finding an exit, whether it be a switch or a teleporter; the goal is simply to advance to the next area. As with its predecessor, Doom II's levels can be completed in a straightforward fashion. However, because the levels are nonlinear players can wander off the beaten path, and those that do are often rewarded with bonuses, like health pickups and more powerful weapons. Due to the larger and more complicated maps with larger groups of monsters, the game had somewhat higher system requirements than the original.

Rather than the player playing through three related episodes as in the first Doom, gameplay takes place over one giant episode, albeit with interludes for when the story develops. Instead of watching the player's progress on a map (as in the original episodes of Doom), the screens between each level simply show a background (a style carried over to the bonus fourth episode of Doom available in The Ultimate Doom, the retail re-release of the original Doom). This also means the player is never forced to lose all of their inventory after completing an episode.

Doom II doubled the number of non-boss monster types and started using bosses from the original Doom as normal level enemies, in addition to adding a new weapon, the Super Shotgun (a very powerful double-barreled shotgun), and a new power-up, the Megasphere.

The continuous 30 levels are divided into four areas; UAC Underground, UAC's Starport (Hellish Outpost), City, and Hell.

Immediately following the events in Doom, the player once again assumes the role of the Doom Slayer. After defeating the Spider Mastermind, the demons of hell open a portal to Earth for the marine, as he has "proven too tough for Hell to contain". After returning to Earth, the marine finds that it has also been invaded by the demons, who have killed billions of people.[10][11]

The humans who survived the attack have developed a plan to build massive spaceships which will carry the remaining survivors into space. Unfortunately, Earth's only ground spaceport has been taken over by the demons, who placed a flame barrier over it, preventing any ships from leaving.[10] The marine battles hordes of demons and is able to deactivate the force field, allowing the remaining humans to escape. Once all the survivors have escaped Earth, the marine is the only human left on the planet.[12]

Just as he sits down to await death, knowing that he saved humanity, the marine then receives an off-planet transmission from the survivors in orbit, who have managed to find out where the armies of Hell are coming from. The message reveals that the demonic base is in the center of the marine's own hometown. He then fights through the city until he reaches the base, but sees there is no way to stop the invasion on that side. He decides to step into the portal to try deactivating it from the other side, entering Hell.

After fighting through the hordes of Hell, the marine reaches the location of the biggest demon he has ever seen, called the Icon of Sin (Baphomet). He kills the Icon of Sin by firing rockets into its exposed brain. Its death causes devastation on Hell, and the portal to Earth is sealed.

Most of the levels were designed by Sandy Petersen,[13] with American McGee playing a significant role as well. The final level, Icon of Sin, contains an easter egg where two of the artists put the disembodied head of John Romero as the sprite hidden behind the icon on the wall which must be hit by rockets three times to win the game. Romero, while playing the level to work on its sound effects, accidentally stumbled upon this in-joke of himself. After realising what his co-workers had done, Romero himself answered by recording his voice saying "To win the game, you must kill me, John Romero", putting it through various filters to distort it, then reverse the recording to create the "demonic chant" spoken by the head upon spotting the player.[14][15] The photo that was scanned for the "John Romero's head"-sprite was from a Businessweek photo shot in 1994.[16]

A 3DO Interactive Multiplayer version was announced to be in development by Art Data Interactive, but it never materialized.[17][18][19]

Doom II was first released on October 10, 1994 (one of the days of the Doomsday rule and exactly ten months after the original), in both North America and Europe.[20][21][22]

• Doom II at MobyGames