Doom II X-Treme

Doom II X-Treme, D2 Extreme, or simply D2X, is a 32-level total conversion for Doom II released on August 12, 1996 by Chuck Lai and the third entry in Lai's X-series (After Doom2X and Ultra Doom2X). While weapon and monster tweaks were done by him, employing an extensive DeHackEd patch and updated graphics, the 32 levels were created by others with some being edits of official id Software and TeamTNT levels. X-Treme gives a larger HP pool for both monsters and the player, while boosting weapons to a whole new level. For example, the automatic shotgun's fire rate is much faster than the default chaingun.

X-Treme was followed by Doom 2 Extreme Gold in 1997.

Doom2X Engine
Starting from Doom2X, Chuck Lai employed 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: DOOM2-XTREME (Doom2x vers. 1.5) running off DOOM 2: Hell On Earth The ENDOOM screen has the following additional text: DOOM2X-Treme (Doom2x version 1.5)

The original release of Doom II X-Treme relied on a hardcoded (and illegal) version of DOOM2.EXE with the DeHacked patch built in, called. This was in line with its predecessor Ultra Doom2X which shipped an illegal executable called (Released May 19, 1996) and ran version 1.3 of the "engine". In the early 2000's an updated release of Doom II X-Treme was made that supplied the DeHacked patch as a separate file and which removed the illegal executable.

Custom weapons

 * Fists
 * Deathclaw
 * Pistols
 * Riot shotgun
 * Dual sawed-off shotgun
 * Highspeed chaingun
 * Electro-magnetic railgun
 * Flame thrower
 * Power Force Blaster

Custom monsters

 * Soldier - this replaces the zombieman. It has 60 hit points.
 * Chaingun Sargent - this replaces the heavy weapon dude. It has 1250 hit points.
 * IAL - this replaces the imp. It has 1250 hit points. It is shown on the TITLEPIC, resembling Glacius from the Rare fighting game.
 * The spectre has 650 points, and can walk through walls, conversely the player can walk through them as well.
 * Comtar - The final boss replacement, who is seen on the TITLEPIC. In addition to spawning enemies, he also throws a volley of exploding fireballs. He has 20 million hit points, which makes defeating him near impossible without cheating in a source port.
 * Other monsters have their hit point values changed.

Other changes

 * The ammo limits for bullets, shotgun shells, and EM-Railgun Ammo (replacing rockets) have been changed to 450, 475, and 475 respectively.
 * The Power Force Blaster only uses 20 cells per shot.
 * The megasphere is now called a darksphere, and gives the player 300% health and 300% armor.
 * The armor and megaarmor set the player's armor to 200% and 300% respectively. The latter is now called X-Treme Armor.

Levels

 * MAP01: System Control
 * MAP02: Well of Souls
 * MAP03: The Gantlet
 * MAP04: Wormhole
 * MAP05: Impossible Mission
 * MAP06: Open Season
 * MAP07: Dead Simple
 * MAP08: Realm
 * MAP09: Stronghold
 * MAP10: Onslaught
 * MAP11: Hunted
 * MAP12: The Factory
 * MAP13: The Crypt
 * MAP14: Genesis
 * MAP15: Dead Zone
 * MAP16: Deepest Reaches
 * MAP17: Compound
 * MAP18: Neurosphere
 * MAP19: The Citadel
 * MAP20: The Death Domain
 * MAP21: Slayer
 * MAP22: The Catacombs
 * MAP23: Tombstone
 * MAP24: Quarry
 * MAP25: Bloodfalls
 * MAP26: Ballistyx
 * MAP27: Anti-Christ
 * MAP28: Heck
 * MAP29: Odyssey of Noises
 * MAP30: Last Call
 * MAP31: Cyberden
 * MAP32: Redemption