Half-Life: Doom

"'Ever wanted to play Doom in the GoldSrc model? Ever had a desire to try out the game you know and love in an improved engine? Well, now you can!'""- Mod description"Half-Life: Doom is a concept for a Doom-themed Half-Life mod by Red-Verse-Writer. Inspired by several Half-Life-themed mods for Doom, in |this particular this mod, the mod inverts this concept by instead revolving around recreating the original Doom in the Half-Life game and its engine.

Gameplay
As a mod for Half-Life, the gameplay of Half-Life: Doom does not significantly differ from the base game. Players are required to navigate through levels, fight enemies, solve puzzles and monitor their supplies of health and armour. Due to its dedication to the gameplay style of the original Doom, the mod features a heavier emphasis upon combat over puzzles, although the latter is still utilized fairly regularly, compared to Half-Life. Progress through the world is as continuous as to be expected, with scripted sequences in place of cutscenes and the player kept in complete control of the first-person narrative throughout most of the game.

The mod features all the weapons and monsters from Doom, Doom II, and Doom 64, as well as a handful of new weapons and enemies. Other obstacles include pits of toxic waste, locked doors that require a keycard or flipped switch to open, enemy fortifications and gauntlets of hazards that the player must transverse. The player is able to perform a high jump by crouching for a period then jumping, combat roll in any direction, and pick up various objects for usage as brief melee weapons. While the player spends most of the game alone, they are occasionally accompanied by non-playable characters, mainly other marines with different abilities. Soldiers simply provide cover fire for the player with rocket launchers and assault rifles, Heavies use heavy machine guns to attack enemies and can use energy shields to protect allies, Medics carry an unlimited supply of medicine that they can use to heal the player and other NPCs while fighting with submachine guns, Engineers will cut open certain doors and repair certain objects for the player while using revolvers to defend themselves, and Scouts can detect hidden enemies and alert the player to a unobserved environment while wielding shotguns to fight enemies.

Returning

 * Fists: The starting melee weapon of the game, replacing the Crowbar from Half-Life. Due to its low damage and poor range, it should only be used as a last resort or when under the effects of the Berserk Power. Doomguy automatically starts with this weapon.
 * Chainsaw: A rapid-use melee weapon that does not have a Half-Life counterpart.
 * Pistol: The starting ranged weapon of the game, replacing the Glock 17 from Half-Life. It is first acquired when Doomguy visits the shooting range in Chapter 1. While it does low damage per shot, its quick firing speed and long-range capabilities, as well as its plentiful ammo and ability to fire underwater, make it a very useful sidearm. Unlike the Glock 17, it cannot rapid fire, instead compensating by doing more damage.
 * Shotgun: A strong mid-range weapon, replacing the SPAS-12 from Half-Life. It is first acquired in Chapter 3 by killing a Zombie Scout. While it is highly powerful at point-blank and medium range, it is ineffective at longer ranges, requiring it to be used as a close to medium range weapon. Unlike the SPAS-12, it does not have a alternative fire mode, as that function is already taken by the Super Shotgun. It reuses the Shotgun model from Deathmatch Classic.
 * Super Shotgun: A extremely powerful close-range weapon, lacking a Half-Life counterpart.
 * Chaingun: A low-damage, rapid-fire bullet-based weapon, replacing the M249 SAW from Half-Life.
 * Rocket Launcher: A high-damage, high range weapon, replacing the RPG from Half-Life.
 * Plasma Gun: A plasma-based, rapid-fire weapon, replacing the Gluon Gun from Half-Life.
 * BFG 9000: The most powerful weapon in the game, replacing the Displacer Cannon from Half-Life.
 * Unmaker: A demonic single-shot laser weapon, replacing the Hivehand from Half-Life.

New

 * Fire Axe:
 * Revolver:
 * Railgun:
 * Assault Rifle: The quick-firing weapon from Half-Life returns in Half-Life: Doom as a weaker but more reliable alternative to the Chaingun. It uses a modified version of the M4 Carbine model from Half-Life.
 * Sniper Rifle:
 * Burst Rifle:
 * Flamethrower: A close-range, high-damage, burst-fire weapon, useful for engaging a group of enemies at once. It is first acquired from the dead clean-suit scientist in the Deimos refinery in Chapter 9. It uses a modified version of the Flamethrower model from Team Fortress Classic.
 * Gas Gun:
 * Grenade Launcher:
 * Lightning Cannon:
 * HE Grenades:
 * Napalm Grenades:
 * Kinetic Grenades:
 * Flash Grenades:
 * Pipe Bombs:
 * Flares:

Tools

 * Fire Extinguisher:
 * Sentry Turret:

Recovery Items and Ammo

 * Armour: Provides a certain amount of armour when collected. Unlike in the original Doom or Half-Life, all armour provides the same amount of protection (roughly 80%), and the normal limit is 999 rather than 100. The colour of the armour collected signifies the amount of armour gained.
 * Green: Provides the player with 50 armour.
 * Yellow: Provides the player with 100 armour.
 * Red: Provides the player with 200 armour.
 * Blue: Provides the player with 400 armour.
 * Black: Provides the player with 666 armour.
 * Small Bullets: Ammo used by the Pistol and Assault Rifle. Unlike in Half-Life, the maximum amount of reserve Small Bullets that can be carried is 500 rather than 250.
 * Bullet Clip: Provides the player with 25 Small Bullets.
 * Small Bullet Box: Provides the player with 100 Small Bullets.
 * Large Bullet Box: Provides the player with 200 Small Bullets.
 * Medium Bullets: Ammo used by the Revolver and Chaingun. The maximum amount of reserve Medium Bullets that can be carried is 500.
 * Ammo Belt: Provides the player with 50 Medium Bullets.
 * Ammo Crate: Provides the player with 150 Medium Bullets.
 * Large Bullets: Ammo used by the Sniper Rifle and Burst Rifle. The maximum amount of reserve Large Bullets that can be carried is 165.
 * Small Ammunition Supply: Provides the player with 50 Large Bullets.
 * Large Ammunition Supply: Provides the player with 100 Large Bullets.
 * Shells: Ammo used by the Shotgun and Super Shotgun. Unlike in Half-Life, the maximum amount of reserve Shells that can be carried is 300 rather than 125.
 * Shotgun Shells: Provides the player with 8 Shells.
 * Small Shotgun Box: Provides the player with 20 Shells.
 * Large Shotgun Box: Provides the player with 40 Shells.
 * Rockets: Ammo used by the Grenade Launcher and Rocket Launcher. Unlike in Half-Life, the maximum amount of reserve Rockets that can be carried is 50 rather than 5.
 * Rocket: Provides the player with 2 Rockets.
 * Box of Rockets: Provides the player with 10 Rockets.
 * Cells: Ammo used by the Railgun and Lightning Cannon. The maximum amount of reserve Cells that can be carried is 250.
 * Plasma: Ammo used by the Plasma Gun and Unmaker. The maximum amount of reserve Plasma that can be carried is 300.
 * Gas: Ammo used by the Flamethrower and Gas Gun. The maximum amount of reserve Gas that can be carried is 400.
 * BFG Cores: Ammo used exclusively by the BFG 9000. The maximum amount of reserve BFG Cores that be carried is 10.

Power-Ups

 * Adrenaline Kit:
 * Berserk Pack:

Returning

 * Zombie Soldier: A possessed undead human soldier, replacing the HECU Marine from Half-Life. They appear as common enemies, and are armed with assault rifles and shotguns.
 * Zombie Sergeant: A stronger and rarer variant of the Zombie Soldier. They are armed with machine guns, rocket launchers and on occasion lightning cannons.
 * Zombie Commando: The strongest, rarest variant of the Zombies. They are armed with chainguns and rocket launchers, and occasionally BFGs.
 * Imp: A brown humanoid demon covered in spikes who appears as a common enemy, replacing the Vortigaunt Slave from Half-Life.
 * Nightmare Imp:
 * Cacodemon: A powerful airborne demon resembling a tomato with a row of sharp teeth and one eye, replacing the Alien Controller from Half-Life.
 * Pinky:
 * Hell Knight: A archetypical muscular goat-like bipedal demon able to control and throw Lost Souls, replacing the Alien Grunt from Half-Life.
 * Baron of Hell: A reddish, stronger variant of the Hell Knight.
 * Revenant:
 * Arachnotron:
 * Arch-Vile:
 * Mancubus:
 * Pain Elemental:
 * Cyberdemon: A massive goat-like cyborg demon that appears as a infrequent mini-boss, replacing the Gargantua from Half-Life.
 * Lost Soul: Small flaming skull-like creatures used as projectiles by other demons, replacing the Hornets from Half-Life.

New

 * Zombie Civillian: A zombified civilian armed with melee weaponry, replacing the Headcrab Zombie from Half-Life. They tend to be armed with wrenches, wooden 2x4s, and shovels. While individually of little threat, they often come in large numbers.
 * Zombie Medic:
 * Zombie Engineer:
 * Zombie Scout:
 * Zombie Heavy:
 * Zombie Scientist:
 * Maggot:
 * Nashrou:
 * Tick:
 * Belphegor:
 * Wraith:
 * Hellhound:
 * Vulgar:
 * Infernis:
 * Succubus:
 * Beholder:
 * Blood Fiend:
 * Grin:
 * Wicked:
 * Roach:

Bosses

 * Sentinels:
 * Sawcubus:
 * Pinkinator:
 * Diabolist:
 * Spider Mastermind: