Say what you want about Left 4 Dead - for all it's tightly integrated mechanics of play, deeply hilarious yet horrifying zombie genocides and beautiful co-op integration, it certainly didn't pack that much of a punch visually. Now don't get me wrong, it was more than technically competent and the environments were very well detailed, the weapon and character models all very realistic and the zombies suitably eerie. But... compare the first five minutes of "No Mercy" with the first five minutes of Half-Life 2: Episode Two, visually. Same engine, same company.
Episode Two opens with a grand reveal shot of a distant, mystical storm - the staging is pitch-perfect, with Alyx standing in front of you, looking out over the ruined city. It's truly a breathtaking sight - and it's followed by possibly the best use of generated physics in the game, the destruction of a bridge. A lot of bridges get destroyed in the Half-Life games. What does Valve have against bridges? Oh, right.
