Welcome to our roundup of the best total conversion mods ever. Presented in no particular order, these are the mods that radically transform our favorite games into something different, with new and improved art, gameplay systems, locations, and adventures. Crafted through years of work, sometimes by large teams of volunteer modders, many of these mods have gone on to become PC gaming classics in their own right.
Here are the best total conversion mods ever made.
Sven Co-op
Link: Sven Co-op on Steam
First released way back in 1999, Sven Co-op is still being both updated and played today. A cooperative mod for the original Half-Life, the mod allows groups of players to battle their way through the Half-Life campaign, where they'll find increased challenges and far more enemies, as well as new maps filled with puzzles and challenges. Over the years hundreds of new levels have been added along with new weapons, improved AI, and lots of customization options. Even if you don't own Half-Life, you can play it for free on Steam.
A Game of Thrones mod for Crusader Kings 2
Link: A Game of Thrones mod site
For Game of Thrones fans, this mod is already at the top of your personal list or will be the moment you try it. It transforms CK II’s medieval Europe into the beautifully realised continents of Westeros and Essos and populates them with characters and events straight from the source material. Marry, mingle, or murder your way through the Starks, Lannisters and many other notable dynasties. Best of all, random game events will quickly spin the world into an enjoyable alt-reality of the fiction we’re so familiar with. This is an absolute must-have for gamers who are fans of the George RR Martin novels and the HBO series.
Counter-Strike for Half-Life
Link: Counter-strike ModDB page
You may have heard of it? The multiplayer Half-Life mod featured such team-based missions as hostage rescue and bomb defusal, each team with its own equipment and goals. With its quick rounds and exciting gunplay, Counter-Strike became an instant hit, and the community began creating maps of its own. Counter-Strike’s emphasis on teamwork and communication helped define a new genre of shooters, and the modders behind it were quickly hired by Valve.
Nehrim: At Fate’s Edge for The Elder Scrolls 4: Oblivion
Link: Nehrim site
Every full-conversion mod comes with a high degree of ambition, but it’s a truly special situation when the mod’s creators have the talent to match. Nehrim: At Fate’s Edge, created by German modding team SureAI over four years, does what the best full conversion mods do: reshapes the features that are lacking in the original game and provide hours of exciting new content. With original voice work by dozens of actors, big changes to several of the game’s familiar systems, and its own quests, story, lore, playable races, and a massive and beautifully designed new map to explore, Nehrim transforms The Elder Scrolls IV: Oblivion into an entirely new experience.
Garry's Mod for Half-Life 2
Link: Garry's Mod ModDB page
Plenty of games have a god mode accessible through console commands, but Garry’s Mod takes the idea to an entirely new level. A multiplayer sandbox limited only by your creativity, the mod has proven to be the ultimate tool for creating webcomics, videos and custom game modes, as it enables players to spawn objects and entities and pose them however they like. You can even play Half- Life 2 using all of the mod’s tools, turning Gordon Freeman from a simple gun-toting scientist into the ultimate expression of your will.
Long War for XCOM: Enemy Unknown and Enemy Within
Link: Long War at Nexus Mods
Harder, longer, and with hundreds of changes to the base game, Long War extends XCOM's campaign, lets you play with up to 12 squad members at a time, adds new soldier classes, voice packs, weapons and technology, and lots of improved and completely overhauled systems. Long War wasn't just a hit with players but with XCOM's developers, who brought the mod team in to work on launch-day mods for XCOM 2, as well as create Long War 2.
The Dark Mod for Doom 3
Link: The Dark Mod site
This mod isn’t simply a celebration of the acclaimed Thief series using Doom 3’s engine, but actually an improvement on some of its features, especially the wonderful and engaging new lockpicking system. The open-ended stealth adventure lets you slink through a gorgeous, highly-detailed gothic steampunk world as you fill your pantaloons with loot and try to avoid detection. Most importantly, the mod comes with its own mission editor, enabling members of the community to create and submit their own custom levels and stories. The Dark Mod was released as a standalone game in 2013.
Black Mesa for Half-Life 2
Link: Black Mesa site
It sounded like an impossible project: building the entirety of the celebrated FPS Half-Life in Half-Life 2’s Source engine, but after eight years of work by a large volunteer team of modders it finally became a reality. While it stops short of recreating the entire game (Gordon Freeman’s leap into Xen is the mod’s endpoint), it’s still a remarkable accomplishment. For Half-Life veterans it contains a mix of new design elements and familiar confrontations, and it’s a also great way to experience the ground-breaking adventure for those turned off by the dated graphics of the original.
Defense of the Ancients for Warcraft 3
Link: Dota Allstars, a recent iteration of the original mod, worked on by IceFrog, who now works for Valve on Dota 2.
Cry of Fear for Half-Life
Link: Cry of Fear ModDB page
While it’s a standalone release now, Cry of Fear began as a Half-Life mod. It’s the story of a man who wakes after being hit by a car to discover his city is filled with gruesome monsters and his mind packed with psychological horrors. The mod has some interesting and immersive tweaks, such as an extremely limited inventory—and the fact that the game doesn’t pause while using it—that bring new challenges as you play through a disturbing, winding story with original animated sequences and multiple endings.
Out of Hell for Unreal Tournament 2004
Link: Out of Hell ModDB page
As Donovan Ling, a lone cop investigating a garbled transmission from the industrial town of Grinwood, you quickly find yourself alone and fighting to survive a relentless zombie invasion. This mod is packed with astounding visuals of a city gone to hell, and a chilling original soundtrack accompanies you as you battle your way through more than 20 harrowing and atmospheric maps. Despite an arsenal of deadly weapons and melee attacks, you’ll never really have time to catch your breath.
