I slightly played GTA III and GTA Vice City, but never owning a PS2 and being extremely picky on my PC games I had to wait for this to come before I actually played very much. The wait was worth it.
Gameplay - Well, in GTA III you escape from the police while being transferred in Liberty City. Now your trying to make some cash an make a name for yourself as the man in the city. In GTA Vice City the people who you work for want to get rid of you so they send you to Vice City to do their dirty work. While their a drug mission goes bad and now you're trying to figure things out and get revenge.
The games is in third person and rightfully so. This would just be weird in FPS mode. In both games you get to steal cars, run over people, kill whoever you want with watever weapon you have, impersonate a police officer, race down fires, hurry people to the hospital, and even drive people around in a taxi. Those are just some of the ways to get yourself some money.
The real meat of the game is in the main story's missions. You'll meet people along the way that will want you to do some odd jobs for them. If you do the jobs they may give you some information you need or may introduce you to other people you will get you closer to your final objective. These missions can range from assassinations to races. There are quite a few different things that can be thrown in there as well too.
The straight missions aren't the only thing you'll have to do. There are hidden packages you'll need to find. There are 100 in each game, many are pretty well hidden. There are also rampages where you'll have to blow up so many cars or kill so many in a certain gang. Next there are garages that want you to bring them a list of cars. Also there are unique jumps spread out across the city that you will need to do. Without doing these and all the thing I said in the first paragragh you won't get 100% completion.
Graphics - GTA games have there own graphical style. The people are not done with any engine you are used to. The people have their own style that is different than other games, but is still pretty realistic. The weapon fire and explosions are done nicely and do impress. The cities are huge and expansive. The draw distance was upped in the Xbox version and it's a good thing.
Sound - The people will have some nice quips when you steal their vehicles or shoot at them. The cutscene voice acting is pretty good. All of the accents used are decent and nothing sounds cheesy. The great part about this being on the Xbox is the customized soundtrack. When you are in a car you'll hear the radio. If you have some songs on your Xbox hard drive then you will be able to set up a station with your own music.
Replay Factor - The game keeps going after you get 100% so you can play forever. You'll probably come back every once in a while just to qunch your thirst for bloodshed. That and you may play through the game again just because it is so much fun.
Bonus - Open endedness. Since the game never ends you can keep on going forever. You'll be the king of Liberty City or Vice City and you can now wage war against civilians or gangs. More games should be like this because I always want to see what it's like after I rule the world.