I’m going to talk about Team Fortress 2 because I love it.
See, this game is the only Multiplayer FPS which has ever grabbed me and got me to play it for, quite literally, hundreds of hours. I have played the Spy alone more than I have any other Multiplayer FPS, and I think the Engineer’s pulling a close second nowadays.
Okay, so to keep things simple I’m going to talk about Multiplayer Shooter Games and call them MPS games, alright?
Most MPS games of our time are pretty shallow and basic. You don’t care about your enemy; even when you get to pick from weapon 1 vs. weapon 2 or crazy ability 1 vs. crazy ability 2 (even if they are still mostly quite bland), your enemy’s weapons and crazy abilities hardly affect your decision-making process. All they do is change the way your enemy can kill you without giving you a cue as to how you should react.
TF2 is different; if you’re a Spy as opposed to a Heavy, the entire landscape of your mind changes. See a Pyro? Your reaction ranges from OH FUCK to HAHA DIE FIRE GUY. You run from certain enemies and charge at others, despite the fact that it’s still more than possible for almost any given class A to kill just about any other class B, with the right approach and skills.
Not only does TF2 offer 9 totally different classes (each of whom plays in a unique way and reacts in a unique way), it also offers a whole myriad of experiences, based on your teammates’ and enemies’ class choices.
Based on my experience with the majority of MPS games, their combat tends to be “shoot” and “charge” and in some of them you need to take cover, especially when reloading.
TF2 with its variety of classes does something exciting and new, granting you the ability to utilize one of nine drastically different classes (this alone would be amazing but not nearly as amazing) in an always very-different playing field. The enemy’s team makeup as well as your own makes a huge difference in how the game in general functions.
… There’s more to be said, but I think this is the one thing that strikes me as most important. TF2 makes a lot of great design choices, and for the most part they exist to put power in the hands of the player — so that when you lose… well, you know.