How Valve made Half-Life 2 and set a new standard for future games

It's Half-Life 2 week at Ars Technica! This Saturday, November 16, is the 20th anniversary of the release of Half-Life 2—a game of historical importance for the artistic medium and technology of computer games. Each day up through the 16th, we'll be running a new article looking back at the game and its impact.

There has been some debate about which product was the first modern “triple-A” video game, but ask most people and one answer is sure to at least be a contender: Valve’s Half-Life 2.

For Western PC games, Half-Life 2 set a standard that held strong in developers’ ambitions and in players’ expectations for well over a decade. Despite that, there’s only so much new ground it truly broke in terms of how games are made and designed—it’s just that most games didn’t have the same commitment to scope, scale, and polish all at the same time.

To kick off a week of articles looking back at the influential classic, we’re going to go over the way it was made, and just as importantly, the thought that went into its design—both of which were highly influential.

A story of cabals and Electronics Boutique

Development, design, and production practices in the games industry have always varied widely by studio. But because of the success of Half-Life 2, some of the approaches that Valve took were copied elsewhere in the industry after they were shared in blog posts and conference talks at events like the Game Developer’s Conference (GDC).

The cabals of Valve

Valve is famous for influencing many things in gaming, but it was most influential in its relatively flat and democratic team structure, and that played out even during Half-Life 2’s development in the early 2000s. While many studios are broken up into clear departments big and small for different disciplines (such as art, level design, combat design, narrative design, AI programming, and so on), many parts of Valve’s Half-Life 2 team consisted of a half-dozen multi-disciplinary small groups the company internally called “cabals.”

Each major chapter in Half-Life 2 had its own unique four-to-five-person cabal made up of level designers and programmers. These groups built their levels largely independently while frequently showing their work to other cabals for feedback and cross-pollination of good ideas. They all worked within constraints set in a pre-production phase that laid out elements like the main story beats, some of the weapons, and so on.

Additionally, similarly sized design cabals worked on aspects of the game’s design that crossed multiple levels—often made with representatives from the chapter cabals—for things like weapons.

There was even a “Cabal Cabal” made up of representatives from each of the six chapter teams to critique the work coming from all the teams.

Ruthless playtesting

Many game designers—especially back in the '80s or '90s—worked largely in isolation, determining privately what they thought would be fun and then shipping a finished product to an audience to find out if it really was.

By contrast, Valve put a great deal of emphasis on playtesting. To be clear: Valve did not invent playtesting. But it did make that a key part of the design process in a way that is even quite common today.

The Half-Life 2 team would send representatives to public places where potential fans might hang out, like Electronics Boutique stores, and would approach them and say something along the lines of, “Would you like to play Half-Life 2?” (Most said yes!)

The volunteer playtesters were brought to a room set up like a real player’s living room and told to sit at the computer desk and simply play the game. Behind them, the level’s cabal would sit and watch a feed of the gameplay on a TV. The designers weren’t allowed to talk to the testers; they simply took notes.

Through this process, they learned which designs and ideas worked and which ones simply confused the players. They then made iterative changes, playtested the level again, and repeated that process until they were happy with the outcome.

Today’s developers sometimes take a more sophisticated approach to sourcing players for their playtests, making sure they’re putting their games in front of a wider range of people to make the games more accessible beyond a dedicated enthusiast core. But nonetheless, playtesting across the industry today is at the level it is because of Valve’s refinement of the process.

The alpha wave

For a game as ambitious as Half-Life 2 was, it’s surprising just how polished it was when it hit the market. That iterative mindset was a big part of it, but it extended beyond those consumer playtests.

Valve made sure to allocate a significant amount of time for iteration and refinement on an alpha build, which in this case meant a version of the game that could be played from beginning to end. When speaking to other developers about the process, representatives of Valve said that if you’re working on a game for just a year, you should try to get to the alpha point by the end of eight months so you have four for refinement.

Apparently, this made a big impact on Half-Life 2’s overall quality. It also helped address natural downsides of the cabal structure, like the fact that chapters developed by largely independent teams offered an inconsistent experience in terms of the difficulty curve.

With processes like this, Valve modeled several things that would be standard in triple-A game development for years to come—though not all of them were done by Valve first.

For example, the approach to in-game cutscenes reverberates today. Different cabals focused on designing the levels versus planning out cutscenes in which characters would walk around the room and interact with one another, all while the player could freely explore the environment.

The team that focused on story performances worked with level designers to block out the walking paths for characters, and the level designers had to use that as a constraint, building the levels around them. That meant that changes to level layouts couldn’t create situations where new character animations would have to be made. That approach is still used by many studios today.

As is what is now called greyboxing, the practice of designing levels without high-effort artwork so that artists can come in and pretty the levels up after the layout is settled, rather than having to constantly go back and forth with designers as those designers “find the fun.” Valve didn’t invent this, but it was a big part of the process, and its in-development levels were filled with the color orange, not just gray.

Finding the DNA of Half-Life 2 in 20 years of games

When Half-Life 2 hit the market via the newly launched Steam digital distribution platform (more on that later this week), it was widely praised. Critics and players at the time loved it, calling it a must-have title and one that defined the PC gaming experience. Several of the things that came out of its development process that players remember most from Half-Life 2 became staples over the past 20 years.

For instance, the game set a new standard for character animations in fully interactive cutscenes, especially with facial animations. Today, far more advanced motion capture is a common practice in triple-A games—to the point that games that don’t do it (like Bethesda Game Studios titles) are widely criticized by players simply for not taking that route, even if motion capture doesn’t necessarily make practical sense for those games’ scope and design.

And Half-Life 2’s Gravity Gun, which dramatically built on past games’ physics mechanics, is in many ways a  concept that developers are still playing with and expanding on today. Ultrahand, the flagship player ability in 2023’s The Legend of Zelda: Tears of the Kingdom, could be seen as a substantial evolution from the Gravity Gun. In addition to offering players the ability to pick and place objects in the world, it gives them the power to attach them to one another to build creative contraptions.

There’s also Half-Life 2’s approach to using environmental lines and art cues to guide the player’s attention through realistic-looking environments. The game was lauded for that at the time, and it was an approach used by many popular games in the years to come. Today, many studios have moved on to much more explicit player cues like the yellow climbing holds in so many recent triple-A titles. As you’ll see in an upcoming article this week written by someone who played Half-Life 2 for the very first time in 2024, Half-Life 2’s approach may have set the stage, but modern players might expect something a little different.

One thing about the environment design that Half-Life 2 was praised for hasn’t been replaced these days, though: a commitment to subtle environmental storytelling. World-building and vibes are perhaps Half-Life 2’s greatest achievements. From BioShock to Dishonored to Cyberpunk 2077, this might be the realm where Half-Life 2’s influence is still felt the most today.

A legacy remembered

Looking back 20 years later, Half-Life 2 isn’t necessarily remembered for radical new gameplay concepts. Instead, it’s known for outstanding execution—and developers everywhere are still applying lessons learned by that development team to try to chase its high standard of quality.

Even at the time, critics noted that it wasn’t exactly that there was anything in Half-Life 2 that players had never seen before. Rather, it was the combined force of quality, scope, presentation, and refinement that made an impact.

Of course, Valve and Half-Life 2 are also known for multiple memorable cultural moments, some of the industry’s most infamous controversies, and playing a big part in introducing digital distribution. We’ll explore some of those things as we count down to the "Red Letter Day" this Saturday.