"Okay.. name me ONE other game that can do half the crazy stuff this game can! Name me ONE! Name a game where you can take a Renamon, nail it to a barrel, turn the barrel into an improvised NASA reject, and launch it into the sky, and then make it explode with a gun from Half Life 2. You can't, can't you? Garry's Mod is ultimately 23,000 games in one, and all you need is a couple old Source games lying around on your hard drive. Simple, isn't it?"
— Bookmaster, Metacritic, Garrys Mod player describing this game
"Garry's Mod has a dedicated following and thousands of servers to choose from and to play online with your friends. There are also tens of thousands of players that play on Garry's Mod on a regular basis. You can also choose to create and host your own Garry's Mod server using a server kit provided to your for G Mod game by doing a simple Google search for the information."
— James Fleckenstein, Rocky Bytes, on Garrys Mod free download
" Garry's Mod is a physics sandbox. Unlike regular games there aren't any predefined aims or goals. The game's makers give you the tools and leave you to play! You spawn objects and weld them together to create your own contraptions — whether that's a car, a rocket, a catapult or something that doesn't have a name yet — that's up to you. If you're not too great at construction — don't worry! You can place a variety of characters in silly positions."
— IGN, About this game
"Freedom to create anything you want: houses, cars, boats, planes, helicopters, or some other crazy contraption: from scratch or from common objects like crates, barrels, household furniture etc. Lots of different gamemodes: from sandbox to racing to City RP."
— Peter, Neoseeker, on Garrys Mod Neoseeker reviews