Steam bonuses for this week include a 50% off deal with Garry’s Mod and a pre-order bonus for Order of War.Garry’s Mod is a ludicrously popular mod for just about every Source game that isn’t Portal: First Slice or bundled Half-Life 2 Deathmatch that functions as a sandbox. Players can create contraptions by welding together just about any item that has appeared in the games, and attaching a variety of physical properties. Want to stick some wheels onto a bit of cardboard and whack some thrusters on the end? Go for it. Want to try and make a plane? Feel free, although the accuracy of the physics means it’ll be hard to balance.I recommend using elastic to attach rocket-propelled sawblades to a vehicle and then driving around like a lunatic, surrounded by whirling death, but then people tell me I’m not right in the head. Now you can be not right in the head too and for only £2.99 GBP, assuming you already have Half-Life 2, Left 4 Dead, Counter-Strike: Source, or any of the other supported titles. You can also make deeply disturbing sexytime with G-Man and Alyx using the body and face posing tools, although even I’m not that wrong.Steam is also offering a pre-order deal on World War II RTS Order of War. Pre-ordering it from Steam will net you two pieces of off-map heavy artillery – one from each of the campaigns. There’s the M115 203mm Howitzer from the US campaign, and the 17 cm Kanone 18 from the German campaign.The Garry’s Mod deal will run until 21 September, while the Order of War deal runs until the game launches on 18 September. Be sure to check out our , and come back tomorrow for our full review, after which you’ll still have time to decide if you want to pre-order the game.