Beams that shake and creak as you struggle for balance. Steel drums that bleed green, irradiated fluid. You are Gordan Freeman, a scientist tasked with stopping the resonance cascade that has torn a rift between our dimension and the beyond. Only in the Lambda Core can Freeman and fellow scientists stand a chance against the alien threat. The entirety of the Black Mesa facility stands between you and your rally point, and its cavernous underbelly isn’t designed for traversal. Although Half-Life wastes no time putting players in the shoes of its unlikely hero, the spotlight is squarely upon its environment.

Half-Life is unique among these 90’s single-player games in that, for much of the game’s campaign, it features a cohesive, grounded design while concurrently experimenting with the 3D space and environmental hazards. The game is split up into two general locations: Black Mesa and the surreal “borderworld” Xen. The former has players platform across tables over electrified water, leap chasms using hanging transport carts, and even shimmy across a crumbling cliff face. Player hazards are practical, with goals defined by mitigating whichever environmental obstacle is fatal.

Half-Life forgoes abstractly telegraphed objective markers. Players are forced to engaging with the environment pragmatically, which allows Black Mesa to occupy a significant presence in players’ minds. When thinking back on Half-Life, I remember the strange bottomless pits bordered with orange warning paint. I remember the claustrophobic, hissing pipes that lead into cavernous metal chambers. The story takes a back seat to the journey, and the journey is Black Mesa. Core to the game’s success is how it impresses upon players that the facility is devoid of human accessibility, seemingly designed without players in mind.

From memorable introductory tram sequence, players are witness to the kind of hazardous environments and waste that take up much of the game’s campaign. This opening sequence hints at what’s to come, but underscores any sense of wonder with the creeping suspicion that the facility itself isn’t safe. The research team has an unknown administrator, hazardous waste flows freely from sewage pipes, and electrical malfunctions convey a unpredictable atmosphere.

Games have explored all manner of these hazardous, industrial spaces, both aesthetically and functionally. Errant Signal’s Chris Franklin touches on the rough division between aesthetic and grounded level design in his “DUSK and the Design of 90's FPS Games” video, and it’s important context for Black Mesa. Franklin notes that Doom’s Mars levels take the aesthetics of grotesque machinery similar to H.R. Geiger’s work in Alien, but the levels are more mood piece than functional within the fiction. None of the actual floor plans make sense as a cohesive facility, which isn’t really what Id was going for anyway. It’s all about the abstract feeling of a menacing space installation without any real grounding.

Then take System Shock 2’s cohesive spaceship design. Unlike Doom or Quake, levels are broken apart by elevator rides rather than teleportation.The floor plans themselves convey a sense of verisimilitude, with practical applications like bathrooms and closets to help fill out the space (Chris Franklin notes these exact features in games like Duke Nukem 3D). Similar to Half-Life, the believable level design heightens the game’s atmosphere while grounding the game’s complex narrative with a sense of tangibility.

Half-Life differs from other 90’s shooters because it’s persistently dangerous atmosphere comes from the pace of exploration and combat. Unlike in its contemporaries, players are encouraged through a combination of level design, hit-scan weapons, and character fragility to approach combat situations delicately. Among the most critical changes is how circle strafing isn’t viable in the game’s cramped, dangerous corridors. Many levels just aren’t suited for combat, due to Black Mesa’s crumbly infrastructure and various pitfalls. Players are more likely to plummet to their deaths than avoid bullets.

Another important aspect key to Half-Life’s pacing is the game’s flat-out ruthless enemies. Dodging bullets is nigh impossible, so hunkering behind cover and picking off enemies from afar is the most encouraged strategy. It’s not quite Call of Duty 4 or Gears, but this kind of “smart firefight” is a shift from free-flowing antics of old school arena shooters. Sections in the level “Surface Tension” even feature branching underground stealth paths vaguely reminiscent of immersive sims like Thief or Deus Ex. Against a tank and two squads of marines, a head-on confrontation isn’t just discouraged, it’s the least efficient way to progress. The anxiety of open battle forces players to pay attention to these kinds of alternative paths, even if they’re somewhat few and far between.

Speed was critical for games like Unreal and Quake to achieve a sense of flow and momentum. Those levels sought to facilitate action where players bob and weave through projectile gunfire in maze-like corridors or small arenas. But Because Black Mesa’s design has a more varied pace, the game osculates between incisive combat and more spacious, atmospheric traversal. These moments are not simple keycard doors from Quake or Doom.

Loose player movement and platforming in particular distinguishes Half-Life’s atmosphere and feel. Black Mesa is a sketchy place from the start, and the game’s many obstacles, like a crumbling sandstone cliff face or collapsing elevator shaft, wrap the facility’s atmosphere with how players are expected to feel about to the environment. Conveyance for traversal puzzles is diegetic, so objectives aren’t always clear.

Inexperienced Half-Life players may incur many accidental game overs, say, attempting to vault over the an object that doesn’t support their weight. It can be frustrating, but Half-Life impresses upon players that danger is everywhere, and that it’s not always fair. To navigate Black Mesa, the environment itself must occupy a large portion of player’s minds. At least far more than if Freeman could simply run and gun it through the place.

On the subject of fairness, the game’s final act throws players a curve-ball with the borderworld Xen. Now you are the invader, and this strange new environment is even less hospitable than before. Where Black Mesa’s obstacles were even somewhat worldly, Xen breaks a few rules that had been taken for granted. The most critical change is lower gravity. Where once players could reliably vault across Black Mesa’s moving production lines or chemical pits, the strange floating platforms that constitute Xen’s introduction are a considerable challenge. There’s no grace period for players to adjust to the game’s new feel.

The other twist is that Freeman is now deep in enemy territory. By forcing players to survive at their most isolated, Xen represents a total realization of the 90’s shooter ethos taken to its most twisted extreme. It’s literally one person against the world, from the flora to the alien architecture. More than any of its contemporaries, Half-Life scales the environmental hazards to mirrors the escalation of enemy and encounter design.

Freeman starts out with basic corridors, dodging lasers and jumping poison, but as vortigaunts and marines are introduced, the game becomes more vertical with more complex platforming hazards. “Blast Pit” and “On a Rail” feature entirely unique mechanics. The former has players dodging a giant claw-like tendril down a missile silo, while the latter requires careful navigation of a tram through the facility’s collapsing rail system.

Survival in Black Mesa depends on understanding the environment’s shortcomings and player movement. Xen goes one further and removes that any context for understanding. Many players feel that the design frustratingly obtuse. I agree that Xen is not traditionally fun, and I admit to only enjoying it more on each subsequent playthrough. The gameplay is even more trial and error than before, and confusing level layouts can stump even the most navigational savvy players.

But these levels are the culmination of Half-Life’s encounter design and environmental challenges. Xen works because it succeeds Black Mesa. If players were forced to play cautious before, Xen is downright brutal. Ammo is scarce and the few new enemy types are the most challenging in the game. Platforming isn’t any more prominent in these levels than Black Mesa, but the alien landscape presents its own memorable hazards.

It terms of layout, Xen is comparable to Doom 2’s Hell — another alien world that played with precarious and abstract vertical space. But Half-Life’s gestures at a complex alien ecosystem distinguish it’s alien world with style and hostility. The space feels more alive and more dangerous. Floating teleportation orbs, poisonous blue flowers, or even those tiny power eating fish that sap the HEV suite’s battery are all alien dangers that players must learn to navigate.

Xen is Half-Life at its most willfully obtuse, but even the Black Mesa portion often proves frustrating. This isn’t a modern game, but the impact of forcing player engagement with a game’s environment through hostile navigation proved central to many modern shooters. The lesson was learned in games like Titanfall 2, Destiny (raids especially), or even Metroid Prime.

It’s interesting to note how the Half-Life remake, Black Mesa, largely sands off the original’s environmental rough edges. While the Xen levels are yet to be released, the Black Mesa portion of the game alters most platforming and puzzles sections. “Blast Pit” was particularly gutted, with the elevator hazards and vertical design completely absent.

The remake isn’t as wild and stressful, its sanitized level design less “cold, uncaring antagonist” and more set dressing. These changes ultimately tarnish the original’s charismatic atmosphere. The old levels were imperfect, rickety things. They challenged players in concert with the enemies, and impressed a sense of life and place. Black Mesa and Xen were not designed for player convenience, and it’s unfair to say that their evocative tone is a blemish. After all, hazard environments were part of what makes Half-Life so unique among 90’s styled shooters.