Garry's Mod allows users to take advantage of the extensibility of the Source Engine through the spawn menu, which enables users to spawn models and maps imported by the user. Since Garry's Mod version 9, Lua scripting has been a notable feature added to the game which allows players to run their own scripts, which expanded potential user modifications by enabling the creation of scripted weapons, entities, vehicles, tools, game modes and NPCs that weren't possible in the game before. Multiplayer game servers will automatically attempt to send any custom content to the client when they connect. Most users prefer to download the Server Data from the Steam Workshop. Examples include game modes such as Trouble in Terrorist Town, DarkRP, Deathrun, Jailbreak, Prop Hunt, and Murder.
Wiremod
Wiremod is a user-created mod that significantly expands the sandbox capabilities of the game by adding a large number of pseudo-electronic components such as microcontrollers, logic gates, buttons, radios, gyroscopes, screens, GPS modules, sensors, laser rangefinders, speed sensors and much more. Wiring these components together allows the player to create a very large variety of electronically-controlled machines. It also features Expression2 (E2) general-purpose controllers, which allow the player to program the chip with a high-level programming language to compute inputs and outputs to control a wide swathe of elements. CPU modules, which use a Low-level programming language, allow similar capabilities, as well as the capability to render graphics on a digital screen, to be able to fully simulate a virtual computer. The use of Wiremod allows the creation of very complex contraptions, and everything from virtual computers to missiles, aircraft, spaceships and space probes, robots and drones; all constructed from components available in-game without the use of modded entities.
Fretta contest
In winter 2009–2010, a contest was held for Garry's Mod by the game's developers to create the best new game mode using a programming framework called "Fretta". Fretta, Italian for "hurry", allows developers to quickly and easily create new game modes for Garry's Mod with commonly required functionality already implemented so the developers can focus on unique aspects of their game modes. Fretta was inspired by a similar fan-created framework "Rambo_6's Simple Gamemode Base". However, for inclusion in Garry's Mod, Newman decided to rewrite it with input and contributions from the original author and other developers. The winners of the contest range from a recreation of the Mafia party game to an aerial combat game mode. The contest winners have been included in Garry's Mod with their own Steam Achievements.
Toybox and Steam Workshop
Garry's Mod 10 added a function called Toybox into the spawn menu (in Sandbox) that allowed players to share and download user-created content. After 2012's release of the Steam Workshop feature, Garry's Mod 13 replaced the Toybox feature with Steam Workshop. With the Steam Workshop feature came more add-ons for game modes other than Sandbox, with nearly 1.3 million Steam Workshop items. A deeper connection to dedicated servers using "collections" (a feature called FastDL for its faster download speeds than downloading directly from the server itself), and other small improvements.
GMod Tower
In July 2009, a small team of developers, working under the names MacDGuy, Mr Sunabouzu, Nican and AzuiSleet, released a server designed for Garry's Mod called GMod Tower. GMod Tower was a server designed as a social media platform for users to get together and play minigames. Within hours of release, the website for GMod Tower reached two million views.
The developers of GMod Tower later formed PixelTail Games, a Washington state-based developer designed to oversee future updates of the server, which shut down in 2016 and was replaced by its own standalone game, Tower Unite. Speaking to PC Gamer about the move to independence, MacDGuy stated that Garry's Mod and the Source engine had limited them on ideas.
Release
Garry's Mod became available as a paid game on Valve's digital distribution service Steam on 29 November 2006. Before this, earlier versions of the game were released for free between 2004 and 2005, with the last free version released on 27 November 2005. As of January 2016, the game has sold 10 million copies.
Reception
Garry's Mod won Computer Games Magazine's 2005 "Best Mod" and PC Gamer US's "Best Mod 2005" awards. The latter magazine's Dan Stapleton called it "ingenious". Garry's Mod also won the Steam Awards 'Defies Description' Award in 2017. Also in 2017, it was featured in Rock, Paper, Shotgun's Have You Played? series.