Half-Life Opposing Force was developed by Gearbox Software and released in 1999.
It is both the first Half-Life expansion, and the first Gearbox game.
Valve's first game was such a success that a sequel was almost obligatory...
However, Gearbox preferred to offer fans a story that ran parallel to Gordon Freeman's.
And for their first game, the gamble paid off handsomely.
Following the disastrous experiment that caused extensive damage to the Black Mesa Research Facility, leading to a large-scale alien invasion, the army has been sent in to silence the staff as well as the aliens.
You play as Adrian Shephard, an H.E.C.U. Corporal tasked with "cleaning up" the Facility.
His squad is aboard a V22 Osprey, which is attacked by an alien ship.
The ensuing crash is terrible, and almost everyone is killed instantly.
Shephard miraculously escapes, but he's lost, unarmed and has received no orders or briefing.
He will have to use his skills to cross Black Mesa and get out of this waking nightmare alive.
Opposing Force relives the Black Mesa disaster through the eyes of Corporal Shephard.
The game begins around the time of the "Surface Tension" and "Forget About Freeman" chapters of Half-Life.
There are no cinematics, and all events are experienced in real time for added realism.
What a pleasure to discover new areas of the Research Facility, as well as revisiting certain Half-Life zones in a new way!
In terms of graphics and gameplay, Opposing Force is pure Half-Life. However, it is not devoid of originality.
The level design is close to Valve's game, the puzzles are original but in the spirit of Half-Life, and the combat is sometimes very violent.
Shephard can also climb ropes, use a kind of grappling hook and even give orders to other soldiers.
Not to mention a lot of new allies and never-before-seen creatures!
HL:OF is a little more difficult than its predecessor, with some monsters being real bullet sponges.
Shephard is equipped with his armoured Powered Combat Vest (P.C.V.) and night vision, which will be useful when facing the hostile creatures that have invaded Black Mesa.
Gordon Freeman's iconic crowbar is replaced here by a Pipe Wrench, which is much more massive: the left click is a normal hit, while the right click is a slower but much stronger charged attack, which is great for smashing even the toughest crates, or for smash creatures to pieces. The Knife is faster but less powerful than the Pipe Wrench.
The Desert Eagle has a laser sight, so its high power makes up for its low rate of fire.
This is a change from the Beretta (or Glock) of the Barneys, which can also be used.
The M40A1 Sniper Rifle is used like the Crossbow it replaces,
but has a cooler, more military look.
The M249 is a powerful light machine gun with an impressive rate of fire, its insane recoil making Shephard himself recoil!
The Displacer is an experimental weapon that fires a ball of energy that teleports the targeted enemy to Xen...
The secondary shot teleports you there yourself, but it only works in certain specific maps.
The Shock Roach is a kind of living, insectoid, electric weapon that replaces the Hive Hand of the Alien Grunts. Its ammunition is infinite. A word of advice:
avoid firing it when you're in the water...
The Spore Launcher appears to be a kind of alien grenade launcher that reloads by literally swallowing... spores.
Remember the Barnacles, those red creatures stuck to the ceiling with their spindly tongues hanging out? Shephard can use them as a grappling hook, which can attach to certain organic surfaces (which gives spores) and even to enemies!
As well as all these new weapons, several from Half-Life are making a comeback:
the SPAS-12, the M16 (or MP5), the RPG, the C4, Grenades and the Snarks too.
Between conventional weapons, experimental weapons and biological weapons, Shephard has everything he needs to counter the Alien threat.
By virtue of his rank as Corporal, Shephard gives orders to the other soldiers.
They will follow you, obey your every command and assist you in battle.
HECU Engineers can cut through doors with their torches.
The HECU Medics can heal Shephard with their syringes,
as well as other wounded soldiers on the battlefield.
As Shephard has not been ordered to execute Black Mesa personnel,
they will help you as you progress.
Scientists in hazmat suits can unlock doors, just like their "classic" Half-Life colleagues.
As well as the friendly "Barneys" Security Guards, Shephard will meet the "Otis" who have eaten a few too many donuts!
They'll give you a big helping hand in combat.
Opposing Force boasts an impressive bestiary, to say the least.
In addition to Headcrabs, Vortigaunts, Barnacles, Houndeyes, Bullsquids, Alien Grunts, Tentacles, Gargantuas and "Classic" Zombies,
This expansion introduces the H.E.C.U. Zombies, the "Zombie Barneys" and the Gonomes, which are bigger and faster zombies that throw putrescent bits of flesh.
Mysterious new Race X creatures have invaded Black Mesa.
Their origin is unknown, and they are Advanced enough to have their own technology, different from the species encountered on Xen.
Pit Drones are small, bipedal creatures that are fast, attack with their claws and fire projectiles with the same precision as a crossbow.
Shock Troopers are bipedal alien soldiers equipped with a Shock Roach. They are very aggressive and behave in a similar way to Alien Grunts.
Voltigores are rather imposing four-legged creatures that act as mini-bosses, but beware of their overpowering electric attack...
And if that wasn't enough,
the highly-trained Black Ops soldiers shoot anything that moves on sight.
They are extremely battle-hardened and make devious, even formidable enemies.
The Assassins are fast, agile women who can make huge jumps,
they're equipped with Glocks and silencers.
The male variant excels in martial arts, and are very effective with their M16 or Sniper Rifle.
The game's soundtrack, composed by Chris Jensen,
is quite different from Half-Life's by Kelly Bailey.
In Opposing Force, most of the action music sounds very military,
with an emphasis on percussion.
But the atmosphere is also full of mysterious, gloomy music...
Building on the solid foundations of Half-Life, and adding plenty of interesting content, Opposing Force has everything it needs to be a resounding success.
The weapons, the new allies and enemies and the music give Opposing Force its own identity, setting it apart from Half-Life.
Between Half-Life Opposing Force and Quake III, 1999 ended triumphantly for fans of exceptional FPS.