Half - Life 2 : Substance GOLD gives the HL2 single player campaign harder challenges and hectic action: 4 gamemodes to test your skills with, a wide array of weapons and 5 different player classes to best suit your gaming style. Welcome to the real Substance, what action is made of!

A fully updated,legit copy of Half-life 2 is required in order to install and play Half - Life 2 : Substance.

System requirements: 1G ram, 2.5Ghz processor for medium detail.

• New single player campaign modes: European Extreme mode is a nightmare/legendary difficulty with all the Substance features but no extra encounters - best for low-level hardwares; the Gordon Tales are an alternate take on Freeman's arrival to C17, which start with a new intro and follow his steps in the Seventeen Years War - think of the chaos of the "Follow Freeman!" chapter,only from the beginning; while Survivor mode is based on health management and trades Halo shields for medikits, so you must save and leech health or an error too many in the canals could prove fatal only in the citadel!

• Bullet time + fast reload as in Max Payne 2,gruesome new gibbing system,friendly fire,open wounds,Critical Hit System as in Shogo (score headshots & melee kills to win health),the weapons' weight affect your walk speed,new Fast-Punch and Throw-Grenade buttons,crosshair disappearing when you run,alternate firemodes,double & long jumps,allies spawning,enemy conversions,incendiary/dark energy shells,battle striders with normal guns and meet bullsquids,houndeyes,assassins and stalkers;

• The HEV FORMS class system

• GORDON FREEMAN:
A scientist and knows how to play defensively while exploiting his enemies' advanced technology to build friendly units and nasty traps. Abilities: HEV Shield and thermal flashlight (burns enemies when focused) Weapons: punch, crowbar, stunstick+manhack, pistol, mp5+grenade (employs hand grenades!), dual combine ball launcher, jackhammer+turrett, bugbait+antlion, berserk ggun (turns super if you use it for a while), explosive-stuffed proximity headcrab (kill headcrabs, win ammo), covenant grenade, quad free fire rpg

• LIQUID SNAKE:
The terrorist leader of fox-hound and his specialties are mass killings and stylish matrixesque executions with any kind of weapon or even bare-handed fights. Abilities: Killing Spree, HEV Knuckles,super throw (splash enemies with crates or barrels), extended bullet time Weapons: punch, tazer, stunstick+manhack, desert eagle, AK47, HK23E, Vulcan minicannon, super shotgun 1/2/4 ammo, cluster incendiary grenade, quad launcher, bugbait+antlion, berserk ggun;

• SOLID SNAKE:
A talented spy who relies on his stealth camouflage to evade capture or to approach and kill unaware foes in close quarters combat or silent arms. Abilities: Stealth Camouflage,Fortune Device (EMP explosion that hurts close enemies and makes impossible for enemy bullets to hit you),HL1 Long Jump Module,Double Jump,Dodge and Speed Weapons: knife, silenced pistol, silenced famas, silenced crossbow with normal+fire+explosive arrows, gravity gloves (choke enemies!), the slam, chaff grenade (converted combines are friendly to you and slaughter each other), quad launcher, bugbait+antlion, berserk ggun

• BIG BOSS:
A infiltrator who knows the ways of the predators of the jungle, healing his own wounds and capping his targets from afar with famed precision. Abilities: morfine shot,nightvisions,crouch mimetism Weapons: hunting knife that leeches life, stunstick+manhack ,flaregun, free fire scoped desert eagle, scoped tranquillizer shotgun, scoped AWP with embedded bullet time, scoped bigger jackhammer, scoped OICW, quad launcher, bugbait+antlion, berserk ggun, proximity headcrab;

• GRAY FOX:
A ninja wrath who shifts through the fabric of reality to coldly murder any living thing fool enough to try and oppose him. This form is locked until you beat the game once. Abilities: Shift to Spectral Plane, Fortune Device Ex and instant gib with any weapon Weapons: progressive katana, sns-50, sawed-off, xm-8, AUG, super ggun, covenant grenade, chaff grenade, slam, quad launcher, bugbait+antlion;