kivan2400 shows us how to make a bomb/rocket in Garry's Mod for Half-Life for the PC. First download Gary's Mod. Once you have downloaded Gary's Mod, begin by placing four barrels in a diamond shape. Alternate four gas canisters between the barrels you placed. Place an exploding barrel in the middle of your diamond. Next put thrusters on the ends of everything you just created, both types of barrels and the gas canisters. Use your duplicator to make as many as you want and launch them.