Doom 3: Resurrection of Evil

Doom 3: Resurrection of Evil (commonly abbreviated to as RoE) is an expansion pack for Doom 3 released April 4, 2005. The PC version was sold as an expansion pack, requiring Doom 3 to install. The Xbox version was sold as a stand-alone game, with Ultimate Doom, Doom II, and the Doom II Master Levels as bonuses on the disc.

The expansion pack included several new monsters, as well as two new weapons.

Plot
Two years after the incident on Mars, research has resumed, led by Dr. Elizabeth McNeil. Once more, strange occurrences haunt the facility. A search team breaks into a chamber deep within Mars, finding the Artifact — a weapon from Hell that the Ancients sealed away long ago.

The lead Marine, upon touching the Artifact, awakens it, the blast wave killing his team and reaching into Hell, alerting the Maledict (Dr. Betruger’s new form). The Maledict sends the three Hunters to retrieve the Artifact. Meanwhile, Hell begins to invade Mars once again.

Differences to Doom 3
Resurrection of Evil introduces new weapons & monsters that were not featured in Doom 3. It also addresses gameplay concerns that were raised after Doom 3 was released.

Weapons
The new weapons introduced in the expansion are:
 * Double-barreled shotgun
 * Grabber Gun
 * The Artifact

Except for the Soul Cube & the chainsaw, all other weapons from Doom 3 make an appearance in the expansion.

Monsters
The new monsters introduced in the expansion are:
 * Bio-Suit Zombie
 * Bruiser
 * Maledict
 * Vulgar
 * Forgotten One
 * Hell Hunter

Except for the boss monsters, the Lost Souls & minor variants of the Zombies that appeared in Doom 3, all other monsters in Doom 3 make an appearance in the expansion.

Gameplay differences
RoE addressed some concerns that players had over game design decisions that were made for Doom 3. Chief amongst these decisions:


 * The absence of flashlight-assisted weaponry - A main game design decision for Doom 3 was to have the player fight in relative darkness, having to make the player choose between illuminating an area or using weaponry to defeat enemies. This decision was criticized heavily by fans of the game, spawning several third-party weapon modifications that would allow flashlight-assisted weaponry. As a result, RoE has a handgun in the game that has a flashlight attachment.


 * Gravity-assisted weaponry - When designing the final interiors of Doom 3 rooms, developers used a 'gravity gun'-like device to make rooms appear more disheveled, as though violent & fatal struggles had actually occurred in those areas. The usage of this type of device, though, was not intended in the game as the gameplay relied upon the player to enter into certain situations where such a device would have given the player a decisive advantage. Another game ("Half-Life 2"), however, had premiered a very similar device as part of it's gameplay. The inclusion of this weapon won many accolades in the gaming community & the knowledge that Doom 3 already had the potential for such a device caused considerable discussions amongst advocates of both games. A few notable third-party weapon modifications utilized this developer's device by converting it into a playable weapon. As a result, the 'gravity gun'-like device in Doom 3 was converted into a "Grabber Gun" for RoE.

Final storyline
Upon defeating the Hunters and gaining their abilities, the Marine shuts down four core systems of Mars to power the old teleporters, sending the marine to Phobos and Delta Labs, then finally into Hell. Battling his way through, the Marine eventually reaches the Maledict. After a fierce battle, the cutscene shows the Marine fire a rocket at the Maledict, only to miss and end up in the Maledict's jaws.

Betruger's head pops out and demands the Artifact. The Marine obliges by shoving the Artifact down Betruger's throat, instantly killing the Maledict and destroying the Artifact, leaving only Betruger's skull behind. The screen fades to white, and Dr. McNeil's voice can be heard saying, “Marine...Marine...Welcome home...”, possibly implying that the Marine was sent back to Mars or Earth. It has also been speculated that the marine died and simply went to heaven because there was no portal back to Mars.

Spoilers end here.

Levels

 * 1) Erebus - Level 1: Main Excavation
 * 2) Erebus - Level 2: Erebus Dig Site
 * 3) Erebus - Level 3: Erebus Labs
 * 4) Erebus - Level 4: Erebus Control
 * 5) Erebus - Level 5: Erebus Research
 * 6) Erebus - Level 6: Erebus Station
 * 7) Phobos Labs - Sector 1: Teleportation
 * 8) Phobos Labs - Sector 2: Molecular Research
 * 9) Phobos Labs - Sector 3: Main Reactor
 * 10) Phobos Labs - Revisited: Teleportation
 * 11) Delta Labs - Unknown: Union Aerospace Research Division
 * 12) Hell