omg u cannot be serious. The best game i have ever played duuuuuude.
The setting is the ninteen-nineties, which means radio stations pump out tunes from that era (not as downright cheesy as the eighties music, but good nonetheless). Your character, Carl Johnson (CJ) is out of prison and back in his 'hood'. What starts as simple gang warfare becomes much, much bigger -- and that is a massive understatement.
San Andreas's map is the biggest game environment I have ever seen, let alone driven across. The size of Vice City would be approximately the size of one of the three districts in San Andreas, and those are connected by countryside roads and highways which spread them apart by more space than their own area. But outwards isn't the only way it goes; you can now travel thousands of feet into the air, in planes, helicopters and whatever else you can steal. If you jump from an aircraft, you can parachute to the ground. You can also now ride pedal bikes and jets and trucks and tractors and speed boats and... well, anything you can think of, actually.
You can also buy properties and live in them, buy businesses and accept missions from them, make money in more ways than I can count. You can customise CJ's appearance by going to clothes shops, hairdressers and tattoo parlors. You can... well, "you can" seems to be the important phrase here; you can essentially do whatever you want. The missions themselves are some of the most downright fun to grace the series, and there is always something new to discover and play around with. Every nook and cranny of the map is overflowing with opportunities.
My only complaint is the game's slightly more serious tone compared to Vice City's silliness (evidenced by the shocking amount of swearing and adult references), but it is handled in a way that isn't unrealistic (like a certain Getaway game I might mention), and the comic undertones are still most certainly there, helped by the tight acting and the well-written script.
It's difficult to say where the series is heading from here, but one thing's for sure: improving upon this game is going to be a massive challenge.