There are few things that better define PC gaming then mods. Nearly as long as people have been playing games on personal computers, people have been making changes to games on personal computers, and it’s come to define the platform and largely set it apart from consoles. Mods do a lot for games, from simple graphical changes and gameplay tweaks, to entirely new experiences the original game designers didn’t think possible. More than most, Valve has come to embrace this scene, and their approval of the modding world really should serve as the benchmark all other companies are held too.

Valve’s first brush with modding came along with their first major success, Half-Life. Half-Life itself was largely built from a modified Quake engine, with around 70% of the engine re-worked by the team. Even before Half-Life, the Quake engine was no stranger to mods, and even before Valve, id Software had embraced the modding world, with the last content pack for Doom 2 being a paid compilation of community maps licensed by id. Almost immediately after its release Half-life developed a mod community, largely born from long-time Quake modders that were familiar with parts of the engine, and it’s this community that’s lent the game an amazing longevity.

Valve themselves spurred this creativity by releasing Worldcraft (not that one), a level design kit that would later be renamed the Source Software Development Kit (Source SDK). Originally just a level editor, the SDK soon evolved into a set of tools, the same ones used by Valve when making their games, and the community went nuts. Never mind the simple single-play map packs, modders soon hacked in multiplayer game modes, including the incredibly popular Team Fortress and Counter Strike, both of which Valve would later purchase and turn into full release titles. There are others too, like Action Half-life, Natural Selection, Sven Co-op or Pirates, Vikings, and Knights, all built on a game that didn’t ship with a multiplayer component.

Eventually Valve released the long awaited sequel Half-life 2, and once again created a new world of modding, helped along by an all new Source SDK, which allowed access to Half-Life 2‘s considerably more advanced technology. The community took over, and the things created rival many real, AAA games both in terms of scope and execution. Listing all of the mods, or even just the ones worth playing, would be too long for this article, but notable titles include Black Mesa, Prospekt, Underhell, and The Stanley Parable for single player, as well as Age of Chivalry, Gary’s Mod, Insurgency: Modern Infantry Combat, No More Room in Hell, and Neo Tokyo for multiplayer. Some of these have gone on to become full release titles, and Black Mesa itself is a Valve approved retail re-make of Half-Life in the Half-Life 2 engine.

As if that wasn’t enough, Valve have shown time and time again their interest in the modding community as a paid profession, something we’ll go deeper into in a second. Portal started out as a student project at Digipen that Valve bought and turned into two full games. Alien Swarm is a remake of an Unreal Tournament mod that Valve licensed and released for free, as well as hiring the team behind it to work on Left 4 Dead and later, Portal 2. Perhaps their best known acquisition is Dota 2, a sequel to the insanely popular Defence of the Ancients mod for Warcraft 3, a mod-cum-game that’s generated millions of players and world-spanning tournaments. While many skilled modders eventually find work in the videogame industry, few companies hire from the mod scene as aggressively as Valve does, and even fewer seem to have the same level of success.

Then there’s Valve’s stance on mods on their games. Where Nintendo actively censors mods, and companies like Blizzard, EA, and Rockstar all spurn mods, Valve openly embraces them, perhaps even more so then well known mod-friendly companies like Bethesda or Bohemia. Nowhere is this more apparent then the Steam Workshop, a mod repository for any game on Steam. Installing mods takes only the click of a button, and the game takes care of the rest. Many games have embraced this system, like Skyrim, Mount and Blade: Warband, and many of Valve’s own titles like Dota 2, Left 4 Dead 2, Portal 2 and Counter Strike: Global Offensive use Workshop for quick and easy modding. Some titles even market themselves on their Steam Workshop integration, flaunting its ease and promoting the community to make use.

It hasn’t always been perfect. There’s the well publicized attempt to integrate paid mods into the Workshop, a disaster so harmful it knocked the pilot game, Skyrim, from Steam’s 100 top games out of even the top 1000. Valve later apologized and explained it was a project they were working on with Bethesda, who has since remained silent on the subject, and moved mod support for Fallout 4 to their own in-game system. The Workshop, like most of Valve’s systems, has very little in the way of administration, and shy of illegal content, nearly anything can be posted, including mods stolen from other mod sources. Still, this hands-off approach has largely endeared Valve to the modding community, a community largely built out of a free spirit ideology, and used to self-policing and skirting legal gray areas.

Mods don’t just change games, they sell them, enhance them, and save them sometimes, and Valve has taken this to heart. Valve was born of modding, taking the Quake engine and turning it into an empire, and by continuing to embrace it they’ve done a greater service to the modding community than all the free source-codes in the world. By fostering the idea of free modification, Valve has proven that the community can do great things, and will continue to as long as companies are willing to let them.