I wouldn't say that I've played many FPS games in my life but most, if not all, contain those red exploding barrels here and there. The earliest example I can think of is Medal of Honour: Allied Assault, which was probably the first FPS I played, and it had quite a few. I'm currently playing Bad Company and they are strewn accross the whole map. What I want to know is where did it start? Which game was the first to have those barrels?