I realized there were a couple of things I forgot to mention in my review, for completeness's sake.

Like I said, I played the PC version, so the quality of the port is worth discussing. GTA4 was originally a console game and later ported to the PC. Overall they did a decent job, with a few quirky instances of its console roots showing through. At first I thought the bizarre shadow-rendering was part of that but from what I hear, the shadows looked strange on the 360 too. The other graphical oddity I've seen is quick camera spins can create a stray texture that obscures the ground at about chest level and then it slowly dissolves away to once again reveal the road and ground, etc. I have no idea if that happened on the 360 or not.

PC controls are okay. They let you remap most keys, but the problems arise when it comes to interacting with nonstandard things. Like the cell phone, which was designed to be accessible with a gamepad. On the PC you have to hit a lot of keys to use it and a lot of keys to get rid of it (if you're not in a vehicle, having your phone out is a royal pain because you can't run or use a weapon). When trying to enter a phone number manually, you can't use the keyboard keys to simply type it in. You have to use arrows keys to highlight each number on the phone keypad individually (ugh). This is similar to entering your initials into the QUB3D arcade game, you can't type them, you have to use the arrow keys to scroll through the alphabet. The game's menus are generally okay, with something just off about them.

There's no ability to take a screenshot!

Like so many games ported from a console, the save system is poor. The only place you can perform a manual save is in one of your safehouses and doing so advances the game clock by 8 hours, because you sleep as part of the save. There are a number of save slots available, which is good. There's an auto-save performed at the end of each mission and many of the sandbox activities, which is also good. Of course, if you load one of those auto-saves, you will not find yourself in the same place where you saved. Instead, you'll be located in the nearest safehouse and the clock will be advanced by 8 hours, as if you slept to do a manual save. And of course, everything in the city will be reset. In a word: LAZY!

Screw up a mission and you're given the option to restart. Sometimes this is the same as loading from your last save though, except without all the ammo you expended during the attempt. There's no mid-point milestone saves, so if a mission is particularly involved and long, you might screw up at the end and have to repeat the beginning part over and over again until you get it all right. The very last mission of the game had this problem. I had to do the same gun battle about a dozen times because the finicky part after it was giving me trouble.

The mouse-controlled driving camera works well except that it annoyingly keeps trying to return back to the chosen camera location after about 2 seconds. And the available camera defaults are all too low for my tastes. So I swing the camera back up and I have to keep compensating for the fact that the stupid game wants to return my camera placement back down. Yeah, that shit might be helpful on a console; not on a mouse-driven PC. And then there the occasions that pointlessly lock the camera into a fixed position: some (not all) carjackings and driving up to pick-up a friend. I can understand the stunt jumps trying to be move cinematic. The other ones make no sense.

Like San Andreas, GTA4 has shops and clothes and accessories. But the selection is bafflingly small. You start near a "Russian" shop which has a small array of frumpy and utilitarian apparel. Once you get to Manhatten, you can access three more store, though 2 of them are the same chain for some reason. One is a hipster shop, with clothes meant to be chic and modern. The other is a formal-wear shop with expensive suits and dress shoes. That's it. You can buy sunglasses and regular glasses, though you have to squint to tell the difference because the sunglasses are so lightly tinted. You can buy a furry hat or a ballcap... or go hatless. Once you've made your purchases and you're trying on your wardrobe back in a safehouse, you encounter the other problem with outfits in GTA4: the interface for changing clothes is atrocious. Use the arrow keys to cycle through clothing for chest, face, head, legs, and feet. It's terribly slow because of the fade-out and fade-in involved with every single change. There's no way to filter what kind of outfits you want to try on. It doesn't tell you the name of the current piece. You can't pick pieces by name, only cycle through them all. It just leaves me wondering why they went through the hassle of putting this stuff in the game and then did a half-ass job of it.