Here's the problem with first-person shooter games: You can only play one of them. The problem doesn't stem from the basic elements of these games. Those are pretty simple. You run around viewing what your character views; you avoid enemies; you kill enemies; and you progress forward. The reason most people end up specializing (at least for a while) in one shooter instead of another lies in the games' smaller details that have big effects over time. These include things like the types of weapons featured, the number and variety of environments, and the accuracy of the game's virtual physics.
When you play these games against other gamers, those are the things that make one game more fun than another. You find a title that has the right combination of details, and you play it until you know the rules of the game's world better than you know the rules of your own.
The way you get good at this is by playing the game solo. Most shooters have an arbitrary story that you play through as you improve your skills. But where most games go horribly wrong at this point, Far Cry does almost everything right. You play as a character abandoned on a mysterious island. As you investigate your surroundings, you'll hide from enemy helicopters, infiltrate strongholds and fight your way towards the center of a volcano. This isn't just a two-dimension killing spree; the details of Far Cry immerse you so deeply in the game that you'll play every moment on the edge of your seat. Few games have attempted this much detail, and none have ever succeeded. Even though it occasionally creaks and rattles (dialogue isn't well-timed with mouth movement, for example), the number of things that work together add up to make a very exciting experience. Imagine your favorite solo-commando movie set in a lush digital world, with you in charge. For about 20 hours.
I'm not going to say that Far Cry is the best multiplayer game available now. If you play it very long, you notice that the details that make it an excellent solo game get in the way in multiplayer matches. Far Cry is clearly about immersing individual players in a complex, single-player experience. And besides, computer gamers currently have access to Unreal Tournament: 2004. Far Cry, however, is easily the best single-player shooter since Half-Life. The battle for the next great action game has begun.