Good game, but overrated
Compared to other FPS games, this feels like your generic shooter. It's much easier to hit people than most FPSs I have played, which can be good or bad depending on how you like to play. It's very fast paced, most battles last a few seconds. Theres nothing fancy about it, just your basic run, crouch, and shoot.
The game is more tactical with smaller groups, but in large ones, basic strategies like "rush here" can be very effective. Mics are almost a must for communication, and the game does provide an ingame system for communicating using microphones. There are also voice-overs which are nice, but not always the easiest way to communicate.
The two most popular modes are "de" and "cs." "de" involves a terrorist team attempting to plant a bomb at a location, and the counter-terrorists must prevent the bomb from being planted or defusing it once it has been. "cs" involves a counter-terrorists team attempting to rescue and bring four hostages to safety, while the terrorists must prevent it. Both are basically the same thing, and generally involve the other team being eliminated rather than the objectives being completed. Overall, the game is fun and much easier to learn than others I have played. I usually play in short periods instead of hours on end, since it does get boring after a while, but not so much I don't come back.