I've played this game for 18 hours so far this week.
It is really fantastic. I've played online multiplayer FPS games of all kinds. I played a lot of TFC and CS back in the day (CS beta 5 on up through CS Source), I've played a lot of BF1942, UT2004, even Goldeneye. Most of the games I mentioned have put their own spin on the team- and/or class-based gameplay with objectives, capture points, respawn timers, rounds, vehicles, you name it, it's all been tried.
Team Fortress 2 is the real thing.
Valve knows what they're doing, they've put a huge amount of testing, tweaking, and polishing into this game, and it shows. The years spent developing this game have paid off big time. Every aspect of the game is centered around making it fun to play. Even the graphical style of the game was chosen to make players easy to see and maps easy to understand, yet it still looks stunningly beautiful, even on 3-year-old midrange graphics hardware (I have a GeForce 6600 GT 128 MB). I haven't had this much fun online since TFC launched in 1999. Valve has finally re-raised the bar and shown the development community how it's done.
