Salut Tech

How Do Game Mods Actually Work?

Published

Four levels of game modding, from swapping assets and using official tools to hooking code and rebuilding games. How the same techniques shaped Counter-Strike, Skyrim, Minecraft and more.

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Sources

S1

Counter-Strike began as a Half-Life mod in June 1999, Valve bought it and hired its creators in 2000, CS 1.6 followed in 2003 and CS2 in 2023.

S2

DotA began as a Warcraft III map developed by Eul, Guinsoo and IceFrog.

S3

DayZ began as an ARMA 2 mod in 2012, while PUBG grew from battle royale mods and sold more than 75 million copies.

S4

Garry’s Mod began as a Half-Life 2 mod in 2004, reached Steam in 2006 and uses Lua.

S5

Riot hired Guinsoo and Pendragon, and League of Legends launched in 2009.

S6

SA-MP adds unofficial multiplayer and C-like Pawn scripting to GTA San Andreas, while its rewritten server successor open.mp listed 1226 servers and 15,264 players on 22 October 2026.

S7

Doom separates WAD data from the engine, WAD is commonly expanded as “Where’s All the Data?”, and id Software released the source code in 1997.

S8

Skyrim uses BSA archives and plugins, loose files can override archived assets and later-loading mods win conflicts.

S9

Minecraft resource packs replace assets, while data packs alter game data and behaviour.

S10

Bethesda released Skyrim’s Creation Kit and Workshop support in February 2012, with Papyrus providing scripting.

S11

Garry’s Mod and Factorio expose Lua scripting to modders.

S12

Skyrim passed 60 million sales in June 2023 and 65 million in July 2026; Nexus Mods listed 142,442 Skyrim SE mods and 13.53 billion downloads on 21 October 2026, rising to 142,554 and 13.55 billion on 23 October 2026.

S13

Team Fortress began as a Quake mod, Valve hired IceFrog, and Gabe Newell wrote that about half of Valve came from the mod community.

S14

Hooks redirect function calls, while Windows DLL search order can let a game load a mod library from its own directory.

S15

SKSE’s loader injects a DLL into the running game without modifying its on-disk executable, a technique its readme notes is also used by viruses.

S16

Skyrim’s Anniversary Edition in 2021 broke native-code plugins; SKSE warned on 14 August 2026 before the move from 1.6.1170 (January 2024) to 1.7.99 (20 August 2026), while Address Library maps functions across versions.

S17

Minecraft Java modding uses mappings, Forge, Fabric and Mixin, with mappings available in 2019 and obfuscation removed in version 26.1 in March 2026.

S18

OpenIV and Script Hook V enable GTA V mods, Script Hook V stops online play, Take-Two challenged OpenIV in 2017 and Rockstar bought Cfx.re in 2023.

S19

Rockstar’s Mod Guidelines of 10 September 2026 restrict mod distribution and monetisation and state that the guidelines are not a licence.

S20

AMD Anti-Lag+ detoured CS2 engine functions in October 2023 and caused VAC bans, which Valve reversed.

S21

Super Mario 64’s matching decompilation finished in 2019 and led to a PC port in 2020 requiring the player’s own game copy, while Nintendo pursued port downloads.

S22

Zelda 64: Recompiled launched in May 2024 using N64Recomp, requires the player’s own game copy and prohibits AI contributions.

S23

RTX Remix intercepts DirectX 8/9 games through d3d9.dll; Portal with RTX arrived in December 2022, Remix entered beta in 2024 and left it in 2025, and the Half-Life 2 RTX demo arrived in March 2025.

S24

Skyblivion requires Skyrim Special Edition and Oblivion and, as of 23 October 2026, remained unreleased after being delayed to 2026.

S25

Melee’s decompilation began in June 2020, reached 47.5% on 27 December 2025 after AI-assisted commit #2007 on 26 December 2025, and reached 100% on 7 September 2026; Chris Lewis’s AI-assisted Snowboard Kids decompilation took 84 days for about 2100 functions versus Melee’s 19,828, with expert help on about 4.8% of commits and a PC port on 2 October 2026.

S26

CS2 has supported Workshop maps since November 2023.

S27

October 2026 reports describe AI-assisted game mashups including Minecraft in Elden Ring and Spider-Man in Gotham, but Tobyn Jacobs had not released his mod and Decrypt did not attribute AI use to individual creators.

S28

Sony announced on 1 July 2026 that new PlayStation console games would stop receiving physical discs in January 2028, while its CFO said on 31 July 2026 that the company would proceed cautiously.

S29

Paid Skyrim Workshop mods launched on 23/24 April 2015 with Bethesda receiving 45%, Valve 30% and modders 25%, then were withdrawn with refunds on 27 April 2015, before Creation Club in 2017 and Creations in 2023.

S30

Baldur’s Gate 3’s Patch 7 brought curated PC mods to PS5 and Xbox through mod.io, while Skyrim and Fallout 4 have supported console mods since 2016.

Footage and music

Music: “Rising Tide”, “Envision”, “Voltaic”, “Newer Wave”, “Brain Dance”, “Ethernight Club” and “Raving Energy” by Kevin MacLeod (incompetech.com), licensed under CC BY 4.0.

Gameplay footage under CC BY 3.0, edited, cut and muted; cropping is noted below.

Short excerpts for commentary, with no reuse licence; owners keep all rights:

Games © their publishers: Valve, Bethesda Softworks / ZeniMax, Mojang / Microsoft, Riot Games, Blizzard Entertainment, Facepunch Studios, Wube Software, Bohemia Interactive and KRAFTON. Freedoom assets © the Freedoom project, BSD licence.

League of Legends footage was created under Riot Games’ “Legal Jibber Jabber” policy using assets owned by Riot Games. Riot Games does not endorse or sponsor this project.

NOT AN OFFICIAL MINECRAFT PRODUCT. NOT APPROVED BY OR ASSOCIATED WITH MOJANG OR MICROSOFT.

Not affiliated with Valve, Rockstar Games, NVIDIA, Bethesda or any other company shown.

Meme excerpts for commentary and humour: “Gru’s Plan”, “Spider-Man Pointing at Spider-Man”, “Drake Hotline Bling” and “Bernie I Am Once Again Asking For Your Support”, from Imgflip templates, with added captions. Short transformed excerpts of about 2-3 seconds; no reuse licence is granted.

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