Essentially, almost all functionality within Garry's Mod (tools, constraints, shaders, menus, etc.) can be altered using Lua scripts and therefore can be heavily customized by the player. The current version of the game does have a price tag and also requires a Source engine game to run.

Most players familiar with Garry's Mod before its commercial release refers to it as Garry's Mod 10. The newer game menu introduced in late 2009. The old, and most iconic, Garry's Mod 11 game menu. Garry's Mod (previously known as GMod 10) is the first commercial iteration of the mod. GMod 9 is the last free version of the modification, and was last updated to version 9.0.4 on the 27th of November 2005. GMod can be used as a map editing tool that interfaces with Valve Software's proprietary editor Hammer to add furniture and small items through its first-person interface, letting users graphically interact with their map. As mentioned, this has allowed an extensive community to build up and create other mods and mini-games within GMod'. While GMod does not possess any actual gameplay value in a traditional sense, it enables the player to freely manipulate all of the objects and features of the Source engine except for the background features. Garry's Mod is a game modification, created by Garry Newman in 2004, and a successor to JBMod, the original sandbox Half-Life 2 modification. Valve also no longer categorizes Garry's Mod as a modification, but rather as a full game, due to its ubiquity and popularity. Garry's Mod no longer requires one, although it is still possible to mount a game to be able to use its content. Before this version, it was required to have at least one Source engine game. The current version of Garry's Mod is version 13, which still receives regular updates via Steam. Some even choose to remain in the sandbox mode to construct contraptions or scenery with the props and maps from most of Valve's games. Many different game modes have emerged with many different objectives and styles. Being a sandbox type game there is no goal as such or a way to win, rather users can modify the game and play the mod however they wish. It allows the player to manipulate objects and experiment with the physics of the Source engine, often with interesting results due to the power of the engine. Garry's Mod, or GMod for short, is a sandbox modification for Half-Life 2 but later became a stand-alone game.

How to mods for gmod