Valve has said that Episode One packs about four to six hours of gameplay, and that sounds about right from our gameplay experience. Veteran first-person shooter fans will definitely have an easier time than casual action gamers, especially with some of the puzzles, which rely on you to quickly evaluate everything in the environment and figure out what you can manipulate with the gravity gun to make your job easier. As with Half-Life 2, there are three difficulty settings in the game, and you can switch the difficulty in midgame, so if you encounter a difficult patch, you can make the game easier, or if you're bulldozing through the game, you can tweak it to be a bit tougher.

FiringSquad: There were also a number of big action sequences in Half-Life: 2. Will Episode One have any epic action set pieces akin to, say, the Strider battles?

Doug Lombardi: Folks will find the action sequences in Episode One are not only plentiful but also constructed with greater complexity than in previous Half-Life games. The introduction of a very strong accomplice (Alyx) has allowed us to place Freeman in the middle of multi-layered combat scenarios – scenarios in which both he and Alyx must make quick decisions and play an active role if they wish to advance.