Garry's Mod, also known as GMod, is a physics-based sandbox game using Valve's Source Engine, which was developed by Garry Newman as a mod to Half-Life 2. GMod requires that you own at least one Source Engine game, such as Half-Life 2, in order to play it. However, you are limited to the props available in the Source Engine games you own, so this should be considered a minimum requirement. The mod was originally available for free -- in fact, the free version is actually still available to download in many places, but eventually the game became a commercial product available through Steam.
There is no specific gameplay objective in Garry's Mod; instead, the game simply enables any number of people to drop in and connect props from the various Source Engine games in any particular variety of ways the players choose. As such, many different general styles of play have evolved over time among Garry's Mod players: while some prefer machinima-type work, others prefer building contraptions or elaborate forts.
As previously mentioned, players are able to spawn nearly any prop that existed in most Source Engine games they own, simply by pointing at the spot where it should appear, then browsing through a pop-up menu for the object in question. The game provides what it calls a physics gun, which appears to be a blue version of Half-Life 2's gravity gun, but in fact allows players to remotely grab objects, move and rotate them around as if they were weightless, and drop them or lock them immovably into a point in space.
It also provides players with a tool gun, which is imbued with a ridiculously vast array of features and is what enables most of the creativity in the game. The tool gun provides many structural abilities, such as welding objects together, attaching them by an invisible ball joint, sliding bar, or axle, creating motors or wheels, or tying them together with rope or elastic line. Together, these tools enable players to construct a vast variety of different devices and contraptions, such as catapults, trebuchets, cars, or the ever-popular Rube Goldberg machines. Advanced players have been known to create machines as complex as large walking mech complete with cannons firing explosive barrels.
Most of the structural features of the tool gun are highly customizable -- for instance, the player may specify that welds should break if a certain amount of force is applied to them, or the friction of an axle, or the strength of an elastic band. In addition, most of the interactive tools, such as wheels, motors, thrusters, and winches, may be assigned remote controls on the number pad. This is particularly useful when attempting to design coherent machines such as steerable vehicles.
The tool gun also has many features that have largely cosmetic use: players may hang lights or lamps from objects, balloons to keep things afloat, colorize them, change their physical properties, and use a special breakout tool to pose the faces of ragdolls. These features are neat for structural use, but really shine when applied to posing and setting up scenes for machinima purposes.
Garry's Mod started as just that; a mod for the Source Engine built by Valve Entertainment, which powers such
games as Half Life 2, Team Fortress 2, and Counter Strike Source. Garry Newman, the creator of the mod, started working on it as a small project with almost no programing knowledge. He kept a thread on the Something Awful forums updated with his progress. Through the forums the mod became extremely popular. Over time the mod grew in to a cult classic. In November 2006, Garry announced that v10 and beyond of Garry's Mod would be sold on Steam for $10. This is a huge accomplishment from a mod with such small beginnings. Garry's Mod remains the most popular Half Life 2 mod to date, with thousands of users playing at any given time.
On January 15th, 2008, an update was released which moved Garry's Mod over to the Orange Box engine. It also added props from Team Fortress 2, Half Life 2: Episode Two, and Portal, which brought big smiles to the Garry's Mod community.
As of July 30th, 2008, Garry's Mod was rated as the 6th most played game available on the Steam Stats page, and is the most popular game that isn't developed by Valve.
Garry's Mod isn't limited to just playing around with objects either. There have been several machinima movies created using Garry's Mod and Valve's Face Poser tool. One of the more popular Machinima groups for Garry's Mod goes by the name Lit Fuse Films, whose more popular G-Mod films include War of the Servers, Ignis Solus, the Rusty Wispers Series ( Daniel and Dennis), and the Melon Series ( Thunder Melon 2, Melon 3, and MelonMan). The quality of these movies speak for themselves, each one showcasing the power of the Source Engine and Garry's Mod.
There is also a strong role playing community in Garry's Mod, where players will simulate every day life inside the game. Maps will be converted in to mini towns, fit with houses, apartments, and stores. This is all made possible due to the Lua Coding system that Garry's Mod brings to the Source Engine.
That's right, Mods of a Mod! It's a bit redundant, but there is also a large mod community for Garry's Mod. Again, this is all made possible do to the flexibility of the LUA coding system. Allowing users to create game modes that other players can easily join in on. It also allows users to create new tools for players to use when making new contraptions. Some of these mods can do things as simple as changing a props color, to
complex things such as simulating air resistance to allow objects to gain lift after they reach a correct speed. One of the most complex mods for GMod is called WireMod. This Mod allows you to program objects in a visual manner. Allowing you to create complex contraptions that allow for even more flexibility inside GMod.
Zombie Survival, or ZS, is a great example of an online server mod. GMod server mods only require Garry's Mod to be installed and then the whole mod is downloaded when connecting to the mulitplayer game. Based entirely on LUA scripting, Zombie Survial is inspired by the then up-coming co-op shooter, also on the Source Engine, Left 4 Dead. The mod is entirely online and pits any number of human players against one zombie player. Sounds easy for the humans? It is at first, but once a human is killed by a zombie he respawns on the zombie team, so all it takes is one mistake and soon the human numbers are dwindling away onto the zombie team. The zombie team is based on the zombies from Half-Life 2 and there are many classes to choose from that are unlocked as more and more humans are killed. One of the main tactics of the human team is to use the Source Engine's physics capabilities to form barricades by pushing around object on the maps from which they can hide and fire behind. Sadly for some, ZS also requires Counter Strike: Source to be installed as most of the human team's weapons are based on the models and skins from said game. Although the popularity of ZS has decreased some, there are still a number of servers active on GMod with a large number of players present.
Garry's Mod is often used to pose ragdolls which will often be made into a short story to form a comic. Posing is when a player uses the Physics Gun to put a ragdoll in a set position. There are ragdolls for every character that appears in Half Life 2, Counter Strike: Source, Left 4 Dead, Day of Defeat: Source, Team Fortress 2 and Portal. There are also custom ragdolls made by members of the community, as well as mods that allow you to use ragdolls from almost any source game in Garry's Mod. Due to the wide range of ragdolls finding the right character for your comic is a very easy thing to do. The best web comics are often funny and well edited, while comics edited in Paint are usually criticized. One of the most well known comics made in Garry's Mod is Concerned, which tells the story of Gordon Frohman and is based off of Half-Life 2. The comic had a huge fan base and came to an end with 204 pages.