Doom 2 Extreme Gold

Doom 2 Extreme Gold is a 32-level total conversion for Doom II released on August 12, 1997 by Chuck Lai. It was the sequel to Doom II X-Treme, which was released the previous year. It is the fourth and final entry in Lai's X-series (Doom2X and Ultra Doom2X were the first and second, respectively).

Like the original, weapon and monster tweaks were performed by Lai, while the levels were taken from Final Doom, Memento Mori II and other community releases.

Doom2X Engine
Like Doom II X-Treme, Extreme Gold relies on an extensive DeHacked patch that significantly changes the behavior of both weapons and monsters. Similar to The Sky May Be, this was called an "engine" named Doom2X. To further give off the impression of an actual engine, at the loading sequence, the following text is displayed: DOOM2X-TREME GOLD (Doom2X v.1.69) running off of DOOM 2: Hell On Earth The ENDOOM screen has the following additional text: DOOM2X-Treme GOLD (Doom2X version 1.69)

The original release of Doom 2 Extreme Gold relied on a hardcoded (and illegal) version of DOOM2.EXE with the DeHacked patch built in, called. In the early 2000's an updated release of Doom 2 Extreme Gold was made that supplied the DeHacked patch as a seperate file and which removed the illegal executable.

Custom weapons

 * Fists
 * Deathblade
 * Pistols
 * Shotgun
 * Auto shotgun
 * Highspeed chainguns
 * Electro-magnetic railgun
 * Explosive Tip Rifle
 * Technoblade

Custom monsters

 * Soldier - this replaces the zombieman. It has 75 hit points.
 * Chaingun Sargent - this replaces the heavy weapon dude. It has 1250 hit points.
 * IAL - this replaces the imp. It has 1500 hit points.
 * Mystic Orb - this replaces the lost soul. It has 400 hit points.
 * The spectre has 1500 points, and can walk through walls, conversely the player can walk through them as well.
 * Black Guard - this replaces the revenant. It has 3500 hit points.
 * Technomage - this replaces the cacodemon. It has 2750 hit points.
 * Summoner - this replaces the pain elemental. It has 4000 hit points.
 * Hell Lord - this replaces the baron of Hell. It has 5500 hit points.
 * Comtar - The main villain is fought twice. On MAP29, he is a final boss replacement, similar to the prequel. In addition to spawning enemies, he also throws a volley of exploding fireballs. He has 200,000 hit points. His true form is fought in MAP30, where he resembles the Heresiarch from Hexen and fires two railgun shots which deal 500 damage each and can instantly kill even while in god mode, followed by a fireball. He has 15 million hitpoints.
 * Other monsters have their hit point values changed.

Other changes

 * The ammo limits for bullets, shotgun shells, EM-Railgun Ammo (replacing rockets), and mana (replacing energy cells) have been changed to 475, 300, 350, and 200 respectively.
 * The Technoblade only uses 2 mana per shot.
 * The megasphere is now called a darksphere, and gives the player 666% health and 666% armor.
 * The armor and megaarmor set the player's armor to 200% and 400% respectively. The latter is now called X-Armor.
 * Armor, health, keys, weapons, and ammo count toward the item percentage in the intermission screen.