Quite a fun game.
Some tweaks made in this game includes the new cop system, which you must get out of the red area when having any stars and make sure another cop doesn't see you while you're out of the red or else the red re-centers around you. This can become a problem when you get only 1 star, since it was easier to escape in the other games, as it should have been. I'm fine with having to get out of the red for 2 or more stars though. The Pay n' Spray is still there, which you can use if one happens to be nearby, rather having to get out of the red, but you can't use it if a cop sees you go in there. You see, this game is just fun, but a little too realistic at times and it's pretty much my only problem with this game. And speaking of realism, cars flip over a bit too easily now, but at least it doesn't start on fire when it's upside down like it did in the other games, which could have been a problem for certain missions.
Speaking of missions, they are pretty good. They generally involve killing people and are not quite as hard as they were in the other games, which can be considered a good thing, considering some missions in the other games were a pain. Other than missions, the game still provides free-roaming fun and of course, the side-missions. The side missions involve things such as vigilant (which has improved in this game), burglary, car theft and races. Assassin is a new side-mission in this game. So, overall, this game provides so much to do and the map is bigger than it was in Grand Theft Auto III, but not as big as it was in Grant Theft Auto: San Andreas, which is kind of a good thing, considering that map in that was just a little too big, while the map here is pretty much just right.
This game has a so-called "episode", which is like an expansion pack and another one is also going to be released soon. Which is nice to hold people over for the next whole new game. But I was pretty disappointed when I heard they are Xbox 360 exclusives through Xbox Live. While they are currently Xbox 360 exclusives, they might come to PS3 in the future. I heard they are even going to be released as stand-alone games on discs too. Maybe they'll eventually be available on PS3 through those.
Overall, Grand Theft Auto IV is a great game, but it feels a little too realistic at times. Other than that, it's still a fun and interesting game to play with a lot to do.