Video Game Modding
Video game modding is the process of altering the original characteristics or aspects of a video game. The ways video games can be modded from a practical standpoint are endless. Mods not only enhance visuals or spice up moment-to-moment gameplay, but can also increase the replay value and depth the original work offers in a way that is novel to both the player and developer.
Modding has been an activity that has existed alongside video games essentially since its inception. One of the very first popular mods, released in 1981, is a parody of a PC gaming classic, Castle Wolfenstein. Aptly dubbed “Castle Smurfenstein,” the mod is a full conversion of the original material and switched out nazi guards for Smurfs, and the unintelligible German became Smurf voices (Dyer, 2016). While still a far cry from what we see in modding today, “Castle Smurfenstein” planted the seeds that would eventually grow with id Software’s first-person shooter golden age classic, “Doom”. Released in 1993, founders Tom Hall and John Carmack of id Software released a WAD file to the public that contained all the tools necessary for aspiring modders to create their own levels. This feature was so popular that just a year later, id Software developed the first attempt at level editors, a consumer-oriented, user-friendly set of tools that allowed users to create their own Doom level (Dyer, 2016).
As the tools continued to get more accessible, modders alike widened the scope of what could be altered, leading to ambitious mods that changed the core gameplay to the point where the mod itself could be considered a new game. An iconic example of this would be the title “Counter-Strike”, which was originally a mod of the game “Half Life”. Developer Minh Le had themed the mod around pitting two opposing forces against each other, with varying objectives depending on the map being played (Dyer, 2016). What was originally thought to only appeal to a small audience ended up garnering enough attention from the public such that Valve, the original developers of Half Life, hired Le and his partner Cliffe and acquired the rights to “Counter-Strike”, intending to release more games in the future (Dyer, 2016). Today, the most recent title in the franchise, “Counter-Strike 2” peaks at over 1.5 million players daily.
Copyright Law and Video Game Modding
Video game modding, when directly altering the core files of any game for any reason, can be a violation of a company’s usage guidelines, and/or copyright or patent infringement. Under copyright law, eight types of creative works are protected: literary works, musical works, dramatic works, pantomimes and choreographic works, pictorial, graphic, and sculptural works, motion pictures and other audiovisual works, sound recordings, and architectural works (Sumner, 2024). Video games can fall under multiple categories of protected works. Video games are also protected by the DMCA (Digital Millennium Copyright Act), which helps to prevent encrypted code and original assets from being improperly accessed by unauthorized individuals (Sumner, 2024). How a game looks and how it might feel may be protected under copyright law. But specific gameplay mechanics cannot be copyrighted; rather, they might be patentable (Simpson, 2025). To qualify for a patent, the invention must be new, non-obvious, and serve a functional purpose. In video games specifically, this would fall under the unique gameplay mechanics a game might have, or an in-house game engine made specifically for the game being developed (Simpson, 2025).
Video Game Licenses
Video game licenses are legal agreements made between video game IP owners and parties who wish to use that IP, such as mod developers. Licenses allow the use, modification, and distribution of intellectual property owned by another party. It would define what parts of a game you can modify, whether it be textures, characters, maps, or game mechanics, and whether you can create total conversions or just minor tweaks. Licenses also may state whether you are allowed to distribute or monetize your mods. In some cases, licenses also state whether a company retains ownership of the mod or if you maintain some rights, and whether they can take your mod down or incorporate your work into official products, with or without compensation.
Angelo Alcid is a senior corporate counsel at Microsoft/Xbox Game Studios, providing legal support for three first-party game development studios: 343 Industries, The Coalition, and Ninja Theory (Alcid, n.d.). He explained to us how different companies might view video game modding and fan art differently.
As Mr. Alcid explained, some companies – including Microsoft/Xbox – have released specific guidelines concerning user-generated content, such as modding and fan art (Microsoft, 2015). Microsoft/Xbox’s usage guidelines include the following:
“Microsoft grants you a personal, non-exclusive, non-sublicensable, non-transferable, revocable, limited license for you to use and display Game Content and to create derivative works based upon Game Content, strictly for your personal, noncommercial (except as specifically provided below) use. This license is limited and clarified by the specific conditions and restrictions below, so please read them. We can revoke this limited-use license at any time and for any reason without liability to you (and if we think you are abusing this license or its intent, you may hear from us)” (Microsoft, 2015).
In this case, Microsoft encourages and promotes the creation and distribution of user-generated content made using elements from their games. However, as detailed by the guidelines, you cannot reverse engineer any of the game systems, you cannot use game content to make inappropriate content, and you cannot monetize your creations directly, only through ad programs on sites like YouTube or Twitch or through donations. By adhering to these guidelines, Microsoft also reserves the right to use, modify, and distribute your content and its derivatives, use your name in connection with it, and do this without requiring compensation, approval, or credit. The license continues even if you stop distribution of the content, and any original ideas you created may be used in future games without compensation or credit (Microsoft, 2015).
Dan Salvato and Doki Doki Literature Club
Dan Salvato is the founder and studio director of video game company Team Salvato, and the creator of Team Salvato’s most successful game, Doki Doki Literature Club (“DDLC”). Team Salvato’s IP Guidelines detailing how fans are permitted to use Team Salvato IP can be found here.
Mr. Salvato told us about his vision and the message he was trying to convey through Doki Doki Literature Club. He also explained the process of protecting copyrights and trademarks relating to DDLC.
References
Alcid, A. (n.d.). Game Developers Conference 2025. Microsoft Corporation. https://schedule.gdconf.com/speaker/alcid-angelo/37931
Dyer, A. (2016, March 18). PC game mods – From Smurfs to Counter-Strike and beyond!. NVIDIA. https://www.nvidia.com/en-us/geforce/news/history-of-pc-game-mods/
Microsoft. (2015, January). Game content usage rules: Xbox. Xbox. https://www.xbox.com/en-US/developers/rules
Rogitz, J. M. (2025, May 9). Can you patent video games? Many times, the answer is yes. IPWatchdog. https://ipwatchdog.com/2025/05/12/can-you-patent-video-games-many-times-the-answer-is-yes/id=188771/
Simpson, M. (2025, April 7). Understanding video game patents and their legal impact. UpCounsel. https://www.upcounsel.com/game-patents
Sumner, M. (2024, February 1). Copyright protection for video game developers: Legal basics. ScoreDetect. https://www.scoredetect.com/blog/posts/copyright-protection-for-video-game-developers-legal-basics