Although
F.E.A.R. Files is an expansion, it isn't necessary that you play
F.E.A.R. beforehand; though it will certainly help you get a better grasp on what is going on. Once again you play as a member of the F.E.A.R. - First Encounter Assault Recon - team, which is a government Special Forces team that deals primarily with paranormal attacks.
Extraction Point's plot doesn't go much deeper than the title. You play as the character from the first game and battle clones and try to make it to the helicopter and escape the city of Auburn. Although the story isn't as complex as the original game, the action holds up well enough that it makes up for any shortcomings. Perseus Mandate is the exact opposite; the story is pretty good with a noticeable drop in action. About halfway through the game, there's a shift between gameplay styles, going from a shooter to more of a reflex-based game where you have to rely on your time-bending powers more than your aim.
The two single-player campaigns are joined by an Instant Action mode, which should be familiar to anyone who played the original on the Xbox 360. Here you battle an army of enemies as fast as you can and have your scores uploaded to an online board. Though a fun distraction, the Instant Action modes really aren't that fun unless you're ultra competitive and just have to see your name high on the leaderboard.
Multiplayer is also around and features a dozen or so maps and a handful of FPS standard match types, like Deathmatch and Capture the Flag. One of the more unique aspects of online matches is that you can use the single-player game's slow-motion ability, which gives the entire match a different feel. However, in order to use the ability, you first need to pick up a power-up which, in addition to giving you the ability, also lights your location up for everyone to see. This adds a slight bit of strategy that you normally don't see in an FPS. The downside is that multiplayer matches can sometimes be hard to come-by on Live, especially now that Halo 3 is out.