Great single player - Multiplayer is shockingly poor
Firstly the single player campaign is unprecedented - the length and depth of the storyline take you deeper into the criminal underworld of New York Liberty City, whilst also allowing a great deal of freedom within the compulsory storyline; there are several opportunities to make decisions, which while not effecting the game in a major fashion leave the player with a sense of the effect of actions (a lesson which should be carried on into life). The storyline contains about 15 hours of gameplay, 10 if you only ever do missions and skip taxi rides to new ones, but obviously, like previous games in the series, there is plenty to do outside of scripted missions - side missions, hidden packages, girlfriends and friends and of course the car "ordering" missions (these have an innovative new twist over the previous games). And obviously the freeroam that made the entire series stand out from the rest, LC is about the size of San Andreas, but sadly without the great open spaces.
That isn't all that has disappeared from the land mark 3rd in the GTA III Series - flyable planes, player customisation (in the form of body fat and muscle), the plethora of weird and wonderful cheats have been whittled down to the bare essentials (not that you'd need them though - its much easier than SA), tanks and the army have been removed for realism, and finally the tongue-in-cheek humour has been toned down for hard talk - again for realism.
Now comes what everyone expects from a game this gargantuan - a decent and reliable multiplayer. GTA IV HAS NOT GOT ONE!!! Deathmatches tend to involve two miss-matched players, any more tends to result loss of connection, but count yourself lucky if you get this far, most attempts either result in you having to start a game where no-one else will join OR you get sent straight back to your last save, where you have to go through the same charade again and again and again. Don't even think of doing the multiplayer missions at the bottom of the multiplayer menu, these are soooooo glitchy that you will barely get past the first stage of each one before being sent back to single player-multiplayer perjury.