Computer Game Mods

Computer games may sometimes be modified by the general public to include new items, characters, enemies, weapons, levels, story lines, models, textures and game modes. These modifications (known as mods) can add extra replay value and interest, and are usually promoted and distributed over the Internet, often becoming an important factor in the commercial success of some games.

In fact, some developers, such as id Software, Epic Games and Bethesda Softworks, provide extensive tools and documentation to assist mod makers; for example Bethesda Softworks' TES-Construction Set for The Elder Scrolls, a tool that the developers used to create the original game worlds.

Modifications that add new content to the underlying game are usually called partial conversions, while mods that create an entirely new game are called total conversions.

For example, a first-person shooter game may be partially converted from a deathmatch gameplay (where players must simply kill as many other players as possible) to a capture the flag game, where players attempt to take the enemy's flag from their base and bring it back to their own flag to score. Team Fortress, one of the most popular mods, is a partial conversion of Quake that used this method. Partial conversions may add new maps, models, skins and weapons; some changes may be even smaller, such as the variables for weapon qualities, physics or movement.

Less common are total conversions in which all original game assets are replaced, as well as a great deal of the gameplay. One example of a total conversion is Counter-Strike, which is based on the Half-Life engine. Whilst Half-Life is a linear, single-player first-person shooter set in a scientific complex under attack by aliens, Counter-Strike is a round-based, multiplayer-only game based on realistic settings between terrorists and counter-terrorists and focussing on rescuing hostages and disarming bombs. In fact, the only thing that Half-Life has in common with Counter-Strike is the genre (First-person-shooter).

In some cases, mods can significantly the success of the original game, with the mod becoming more popular than the original. In those cases, players often refer to the original game as vanilla, such as vanilla Quake 3.