One of the brilliant things about Valve is their amazing detail and quaility they build their games around. They definitely didn't forget about this when they were making Team Fortress 2.
Originally TF2 was released in The Orange Box for the PC, PS3 and Xbox 360 along with Portal and Half Life 2 : Episode 2. Due to it's success Valve later released it as a standalone game exclusively for PC. Team Fortress 2 experienced good sales when it originally went on steam and quickly became one of Valves flagship games. TF2 also got a very good 92 rating on Metacritic scoring just a few points less than games like San Andreas and Portal 2.
On June 23rd 2011 Valve announced that Team Fortress 2 would go Free To Play leaving players who bought the game confused. Valve later announced that since the game went Free To Play their profits had increased by 12 times because of new players buying new items through Micro - Transactions.
In the game you play as either a RED or BLU soldier. You fight the other team in different game modes like Team Death Match and King Of The Hill. At the start of the match you choose a class, each class has different weapons and physical properties. The heavy has a crazy minigun and the spy can disguise as other characters and go invisible. The only downside to TF2 is that it's an online only game unless you want to play offline practice, this means that if you are on the move or have dodgy internet it may not be a good experience. One of the main points of Team Fortress is playing and getting new items and clothes through trading, accomplishments and Random In Game Drops.
Team Fortress 2 overall is a very good game and it's a plus that it went free to play another plus is that you can actually make money off it by selling your virtual items !!
GO AND GET IT NOW :D