Garry’s Mod is one of the most classic HL2 experiences you can find, without having to play the original game of course. But if you want to truly experiment and have fun with this sandbox, you might ...
To equip mods, enter the pause menu and navigate to the Inventory tab at the top of the screen. You can also press ‘i’ (on PC) to jump to the Inventory menu. Once in the Inventory, go to the Mods tab.
If you've been having trouble with Garry's Mod lately, specifically the error, "Unable to shade polygon normals," don't take it to the Steam forums. You can solve that issue rather easily -- by buying ...