Very well done and enjoyable game especially in a few specific areas. I'm consider myself more of a dabbler when it comes to games. Although I play a lot of them, I rarely tend to finish them as most games imo don't really have a compelling hook to drive me to complete them. Even in prior GTA's I've been known to take mammoth breaks after getting frustrated with certain aspects of the game. I've got Halo 3 and COD 4 sitting here untouched except for their multiplayer sections so when a game compels me to finish it and in a relatively short amount of time, that's something I take note of.
As far as breaking the game down, there is no doubt in my mind that the single biggest flaw of prior GTA's have been improved a hell of a lot and I'm talking about the combat. The more I played, the more and more I enjoyed it and realized it is a really comprehensive system of combat that allows a great deal of freedom. The lock on/free aim combo is very full featured and I used both through the game. The cover system while problematic in some cases due to the different geometry of the world really is extremely useful, fun, and creates some damn cinematic battles. It really is night and day. People who complain that the combat system is broken or is no better than other GTA's lose all credibility to me or are misremembering how combat worked in prior games. It is a huge difference and makes combat which was a weakness of the game a strength. There is still lots of room for improvement. The controls are a bit overly complex imo for it when you take into account the lockon. And moving around the environment and in cover is a little trickier than it needs to be. But it is a big step up from where they were and I can only imagine it will be even better in the next game.
Another major part of GTA is of course the driving, and while I wouldn't consider the total improvement that combat was it is different and does bring some things to the table. The weird thing is it totally depends on the vehicle. Some vehicles and bikes feel dead on. But some feel sort of "skitchy" or too "squirrely". Sadly a lot of the bikes fall into this category for me and I found myself not wanting to use bikes as much as in prior GTA's because of this. All of the really good cars handle pretty damn well though so I think it's more a case of working on the physics or handling characteristics to get those corrected or make them more enjoyable. The driving while shooting controls are also a little difficult. Perhaps that should be challenging but right now it feels clumsy because I have to hold certain buttons while driving and it sorts of feels like patting my head while rubbing my stomach at the same time. Same with trying to chase somebody down and use that focus button to try to center the camera on them.
The mission structure and gameplay choices seems to have been paired down and more focused for GTA 4. This has an upside and a down side to me. It managed to get rid of a lot of the mission types I really hated or just found frustrating that would often stop me from playing past ones. On the negative side, it reduces the variety type of missions which is a bad thing Like the mission where you try to stay on the truck and have to climb forward on it without getting thrown off was awesome. I wanted more variety in the missions like that. This is partially due to some of the features not making it over from SA. There is no stealth aspect to the game and while I understand why they focused and removed some of these things to get GTA 4 done, its still a little disappointing that you don't have the variety of missions like you did in SA. Especially stealth missions. This GTA was also a little easier to me than some prior ones but that also may have to do with the improved combat controls which meant I could handle the combat missions a lot better than I ever could before.
The area outside of combat where the game took the biggest leaps imo are in storytelling. This is one fine GTA game imo in that regard and was the biggest aspect as usual in a GTA title that kept me hooked. They finally were able to setup and tell the story of a lead character who has a viewpoint and feels like he is able to change both the story and himself. All prior GTA's for me have sort of felt like the main character was simply a guy who things happen around. The other characters are the ones with emotion and are interesting. In this GTA though the lead character is the most interesting one and he interacts with the world. That is the way it should be and that is where most storytelling in games fail and this GTA worked exceptionally. The ability to make moral choices is huge to immersing yourself in this game.
The moment when you are on the way to the airport to kill the guy or not is one of the best moments of a videogame I've ever experienced. My heart was pumping. And when i got there and the guy was in front of me I really didn't know what I was going to do. Thats a terrific level of immersion when you've been able to reach that point and do that the player. Early in the game, I had made some poor choices when the moral aspects presented themselves because I was thinking in traditional video-game terms like, oh the game probably wants me to do this because its hinting at it, or I'm going to do this because I'll probably get more good stuff If I do it. (Sort of the I better be evil/good so I can power up my evil/good side which I've become tired of in some of the moral choice RPG's out there). But what I loved about GTA 4 is that these are really moral choices you are presented with. It's beyond will I power up my light side or evil side. It's what do I believe and that's when I knew they had done something special.
Personally for me when you make that choice that is the real end of the game to me. The rest of the game that you play out is quite enjoyable and you have another great choice when you decide to kill Dimitri or not, but for me the games high water mark is the airport scene. The drive there (where Marvin Gaye's, "Inner City Blues" was playing on the radio which was a random lucky bit of perfect song choice for that moment). The decision. And the drive back in silence where Niko says to turn off the damn radio and the stupid ads. The game could have ended right there for me and I would have been happy. To be chasing a guy who haunts you the entire game from a past that has only been told by your character and to really believe in that decision and be given the option to kill or not kill him is some poetic stuff.
The actual ending ending is also quite good for me. No rah rah yeah everything is happy. You get the sense that this story is told but these characters and their trials and tribulations will continue is about as good as it gets. I thought the cheeky you won achievement and the you won line from his friends was a subtle jab at the typical gamer who wants to win and be heralded as the awesome gamer. It puts the focus right back on Niko and asks the question has he really won and at what cost. Great stuff. I hope in the future the moral choice things extends even deeper in the next GTA games and even extends beyond just who you kill but who you treat in certain manners or if you stand up to certain characters and say I'm not doing this particular mission or something. I love the notion of unintended consequences so there is a lot of room for them to expand in this area.
I have more thoughts and observations but I'll save them for later as this post is getting a bit long anyway.