Doom II: Hell on Earth

Doom II: Hell on Earth is an award winning first-person shooter video game and the second title of id Software's Doom franchise. It was originally released for MS-DOS computers in 1994 and Macintosh computers in 1995. The Macintosh version was developed in Austin, Texas by developers such as Brett Butler. Unlike Doom which was initially only available through shareware and mail order, Doom II was a commercial release sold in stores. Master Levels for Doom II, an expansion pack that includes 21 new levels, was released on December 26, 1995 by id Software.

Due to its popularity and success, Doom II was later released for the Game Boy Advance in 2002, the Tapwave Zodiac in 2004, and on Xbox Live Arcade in 2010. The release of the original Doom source code has facilitated ports to many other platforms, including the Apple iPod, and several types of cellphones. On August 13, during the QuakeCon 2009 media conference, it was announced that Doom II would be ported to Xbox Live Arcade, and was released in May the following year.

Immediately following the events in Doom, the player once again assumes the role of the unnamed space marine. After returning from Hell, the marine finds that Earth has also been invaded by the demons, who have killed millions of people.

The humans who survived the attack have developed a plan to build massive spaceships which will carry the remaining survivors into space. Unfortunately, the only space port that's capable of launching such ships has been taken hostage by the demonic invaders,

who have placed a force field over it, causing it to malfunction. The marine then battles millions of demons and is able to deactivate the force field, allowing the remaining humans to escape. Once all the survivors escape Earth, the marine is the only human left on the planet.

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

After fighting through the hordes of Hell, the marine reaches the house of the biggest demon he has ever seen, called the Icon of Sin. He kills the Icon of Sin by firing rockets into its exposed brain. The Icon of Sin's death results in the destruction of the Hellish portal. Now with Hell in ruins, the marine joins with the other humans in an effort to restore life on Earth.

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 32 levels (two of which are secret levels that can be accessed from level 15), 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.