Thread:SlyCooperFan1/@comment-26016568-20150309220227/@comment-1824272-20150310005555

Steam doesn't record anything. You'll have to find another program that records your desktop. Fraps is usually the one everyone goes for. Unfortunately, Assault Horizon and Fraps together usually slows down the computer and therefore the gameplay and recording, so your mileage may vary, but definitely look through Google and see what you can find.