The Top 10 Game Mods Of All Time

History's best user-created PC game modifications are highlighted in this list of influential mods.

Greg Finch

What is a mod? Mods, short for 'modifications', are user-made edits made to PC videogames, the game equivalent of fan fiction. Traditionally free, they range from minor code changes to fix bugs or smoothen gameplay to 'total conversions'—complete overhauls of art assets to form an entirely new experience. Imagine the hellraising levels of Doom swapped out for the green blocky pastures of Super Mario Bros, or a futuristic strategy-shooter rebuilt to drop the player into historically-accurate WWII battlefields.

Game mods have grown in stature over the past generation, as level-building became less technical and more encouraged, leading some of these user-made creations to even be championed by the game's original developers. At the core of the idea, mods enable an enthusiastic fanbase to build upon and improve the developer's creation. Trying to round up a canonical list of 'the best' mods is frankly impossible—practically each semi-successful PC game of the past 20 years has spawned a dedicated modding community. This is merely an effort to identify those mods that have played a role in the current culture of major release games, the ones that proved most influential and achieved crossover success, with some even recognized by the industry and refitted for commercial release.

It is difficult to attempt a discussion of the mod history without explicitly mentioning Valve Software, developer of Half-Life, Left 4 Dead and Portal. Valve was the first major game developer to embrace and actively encourage this creative aspect of game communities, routinely hiring fans that were exceptional level designers to work on official Valve projects.

In countless interviews, Valve founder Gabe Newell professes this path as the way to garner serious attention from industry professionals: "The best thing to do is to start making content using the mod tools that are out there. Whether you use Civilization or Warcraft III or Hammer doesn't matter as much as that you are building and shipping stuff to customers, getting their feedback, and then iterating your work. Mod development is better in a lot of ways of both honing your skills and demonstrating your talent to a potential employer than work experience as there are going to be fewer institutional barriers and creative constraints to limit the work you do."

Just this past month, Valve Software announced that the three winners of its 'Summer Mapping Initiative' level-building community contest for Portal 2 would, in addition to customary prize packs, have their work featured to download by all PC and Mac users and probably in an upcoming DLC pack on console versions.

Due to the evolving nature of open-source modding and the fact that certain engines (Quake, Half-Life's Source engine) are being designed with user customization in mind, our list naturally skews towards the present day and higher-profile titles. That isn't to discount the work of thousands of modders previous, notably SNES Rom hacks, Battlefield mods and RPG mods for Bethesda's Morrowind and Oblivion. In fact, the first title with user creation tools was Adventure Construction Kit in 1984 for Commodore 64 and Apple II.

Aliens TC (1994) by Justin Fisher
In this first total conversion mod, Justin Fisher deftly translated the foreboding atmosphere of the early levels of id Software's Doom to tell the haunting space horror story of Aliens in his complete overhaul of the game's assets. According to legend, the mod was so popular it overshadowed the release of Doom II in the Doom newsgroups, and Fisher turned down multiple offers from game studios (Aliens TC heavily influenced 1998's Trespasser by Dreamworks) to finish his college degree.

Team Fortress (1996) by Robin Walker, John Cook and Ian Caughley
Team Fortress was the first widely popular PC mod on id's Quake 1 engine, with innovative class-based gameplay that put new emphasis on team cooperation and player strengths and weaknesses. Players selected from eight distinct classes like "sniper" and "medic," and were forced to communicate and play in tandem. It also notably happens to be the FPS to introduce headshots to the genre.

Chaos DM (1998) by Chaotic Dreams Group
Chaos DM revamped Quake II with a plethora of inventive weapons (broadswords, crossbows) and bonkers powerups (jetpacks, antigravity), fostering a creative testing ground that would influence competitive multiplayer games of the future. Halo developer Bungie reportedly tried to adapt equipment originating from Chaos DM into 2007's Halo 3, the item being 'The Vortex': a mini-black hole that sucks in all nearby matter, curving bullets and swallowing players.

Counter-Strike (1999) by Minh Lee and Jess Cliffe
The granddaddy of all mods. This best-selling multiplayer modification revolutionized online PC gaming and introduced millions to the first-person shooter. Hard to believe that it began as a fan-created mod for Half-Life. Minh Lee and Jess Cliffe converted the vast alien-filled world of Valve's single-player Half-Life into a terrorist/counter-terrorist multiplayer desert battleground whose internet presence spread like wildfire, prompting the designers to be hired by Valve for a retail Counter-Strike release and tens of thousands of LAN parties organized for 8v8 teams across the world.

Defense of the Ancients (2003) by Eul, Guinsoo and IceFrog
This Warcraft III mod replaced the monster-filled original with mythology-laden maps and units of heroes and ancients, spawning one of the most popular RTS mods of all time, as well as its own genre. There are reportedly 20 million dedicated players in China, and the official sequel is due this year from Valve in collaboration with mod creator IceFrog.

Red Orchestra (2003) by [RO]Jeremy
The award-winning Red Orchestra did the WWII FPS better than all other comers in 2003, outflanking Call of Duty 1 and Battlefield 1942. Designer [RO]Jeremy converted the futuristic sci-fi arena shooter Unreal Tournament 2004 to intense full-scale recreations of WWII battles on Europe's eastern front, kickstarting the shooter trend toward gritty realism, which now transparently dominates most of the industry.

Garry's Mod (2004) by Team Garry
Garry's Mod is a user-friendly object sandbox that allows the player to place and pose assets in the Source engine, spawning creations ranging from physics experiments and acclaimed webcomics. It is to-date the most successful indie product on Steam, the largest PC digital download service.

Dear Esther (2008) by Dan Pinchbeck
Dan Pinchbeck's Dear Esther, a story-driven experimental ghost story, was unveiled in 2008 and is now being commercially redeveloped by Jonathan Blow of indie cult hit Braid for commercial release in late 2011. In this Source mod, the player receives and deciphers text fragments while searching for a beacon on an abandoned island, with heavy allusions to the Biblical story of Paul on the road to Damascus.

CUBE Experimental (2009) by Dennis Weich
Game developer Bethesda Softworks has a storied tradition of offering 'construction sets' for their RPG releases Oblivion and Morrowind for users to tinker and create with. German modder Dennis Weich of the group SureAI released this experimental Portal-inspired atmospheric expansion to the Fallout 3 story where the player is trapped inside an ominous white cube prison and puzzles their way to freedom through traps and enemies with a dark, slowly unraveling backstory. According to Bethesda, Cube Experimental is "one of the most impressive mods for Fallout 3".

Black Mesa (2011/12) by Black Mesa Team
Black Mesa is a total conversion mod to retell the Half-Life 1 story through the vastly improved Source engine of Half-Life 2, revamping the entire single-player experience with an exhaustive overhaul of detailed art assets. The designers periodically update with progress, and recently demoed the first few levels to members of the press. Black Mesa consistently tops lists for most anticipated upcoming mods.

Did your favorite mod not make our list? Add (and defend!) your own suggestions in the comments section below.