I am, admittedly, not a big fan of shooters. Specifically of the first person variety. So when I enjoy an FPS, it's a big deal. It's an even bigger deal when I find one to be completely awesome.
Enter Team Fortress 2. A class-based shooter that is fast-paced, team-oriented, and bucketloads of fun. This is one of the rare times I'll take a game and put it on a pedestal. The game has its faults, but they're mostly balance issues that I believe will be ironed out in time.
The great, great thing about this game is that it avoids the big pitfall of the shooter - generally you are either killing, or being killed. This very basic ideology is the downfall of many, many games, as there are really only so many ways you can kill or avoid being killed without one way being clearly better than the other. In single player games this means you strive for that one, most efficient way, and in multiplayer games it means you either choose the best way or end up frustrated.
TF2 manages to squeeze 9 completely different playstyles out of "kill or be killed," each of which is fun in its own right. You can switch from the fast, furious Scout, who can't take a hit but is incredibly mobile, to the Engineer who sits back and builds defensive equipment. Not only are these classes a great variety, they also provide enough difference in style of play that almost anyone can find a character they enjoy and can play effectively. This character usually ends up being a gateway drug into the other classes of Team Fortress.
In addition to these, the geniuses at Valve (creators of TF2 for the uninitiated) have begun putting out packs of new achievements and weapons for each of the classes. Unfortunately, here there is room for improvement, so let's run down a quick list:
One at a Time
These packs are released one class at a time, and usually several months apart. This means you usually get a large influx of whatever the new class is for quite some time while everyone gains the new achievements, which are a problem in and of themselves...
To unlock the new equipment, you have to get a certain number of achievements. This would be fine except that some of the achievements are silly (see: example) and result in people doing stupid things they wouldn't normally do to unlock achievements. Silly and fun achievements are fine, but they shouldn't be required for new equipment.
Either add more standard achievements that reward good gameplay (without upping the amount needed for new equipment), or remove achievements as the qualifier. Maybe use kills/points instead?
Some of the new equipment is great (see: the Pyro's Flare Gun), adds a new dimension to the character, changes the way you should be playing, and fills out some gaps (while creating new ones, which is very important).
Some, however really do nothing for the class (see: the Heavy's KGB). They fall short of being useful, and are really only a status symbol. In the example of the KGB, the heavy really shouldn't be meleeing much at all, and when they do, slower swing speed and more crit is not at all useful. It fills in no gaps, it creates no interesting situations, and in general is somewhat half-assed.
Finally, some are simply clear and better options than the weapons they replace (see: the Medic's Blutsauger). Once you get these items there's really no reason to ever switch back. This essentially introduce an artificial form of "leveling" into a shooter, where it has no business. If the class needed a boost, it needs it across the board, and if it doesn't, there's no need to make a weapon simply better. The Blutsauger loses the ability to crit, but crits, in addition to being a rare occurence in the first place, aren't really a concern for the medic. There is no reason to not use this weapon, and that's a poor design decision.
Altogether, TF2 is still an awesome game, and these updates certainly don't detract from the experience in any way - they are additional and never detrimental to playing. I only think if the new equipment erred on the side of being more interesting, and they released updates for two classes at a time, we'd be in much better shape.