The cover system: Because you can’t just pile in anymore

Already alluded to in 'Weapons and targeting' GTA IV's cover system is worth noting in isolation because it has paved the way to a new style of mission. That of the tactical interior shoot-out. What that means is where in old GTA gun-battles were often confusing, luck-based ordeals, Niko has the ability to take cover behind anything using the left bumper and then use the camera to look around or over objects and fire from safety.

He can even slide between areas of cover. This puts the outcome of a gun battle down to your patience and skill, rather than the lap of the gods, as without this sharp, tactical way of working your way through droves of enemy in confined spaces, you'd be a dead man. Make no mistake, it totally changes the face of the GTA experience and leaves you relishing the potential of duel rather than fearing it.

On the mobile: Your link to the criminal underworld

Roman gives you your first phone and promises one day you'll get a better one which will be a sign you've 'made it'. Well, you do get a new one, from Playboy X, and that's when the real fun starts. Yes, you get a gold camera phone innit. Not only is it your way of communicating with characters in the game in a totally uncontrived manner, it's your key to going on leisurely dates, dinners and days out, keeping track on time-critical missions (with the organiser function) and taking pictures of hooker's asses with the camera.

While your phone is the single most important piece of kit you'll get in the game you can also purchase ring tones for it off the in-game internet, buy new 'themes' or just dial up 911 for kicks and watch the police arrive and bumble around looking confused.

Oh, and should you want to know what that tune is playing on the radio, just dial up Zit on 948-555-0100 and the service will text you the name back. Told you it was useful.

Sound: Music to your ears

The funniest line in GTA IV comes totally at random on the Integrity 2.0 radio station when stalwart radio presenter Lazlow interviews a Central American hot-dog vendor about the plight of being an immigrant worker. After establishing it's a non-story as the hot dog vendor reveals he is, in fact, quite happy with his lot, Lazlow gets a bit mouthy and in response the incensed interviewee retorts, "Hah, why you called Lazlow anyway? That's like some kinda clowns name."

Honestly, it's funnier when you hear it for yourself. The point is, the talk radio stations of Liberty City are as alive and full of biting insight as they were before. And, as featured in San Andreas, Rockstar has pulled that clever trick where when you commit a crime, it appears on the radio news show reinforcing the sense that Niko is having an effect on the way a living world evolves.

Equally, the music, one of the most crucial elements of the GTA experience is as varied as it is full of surprises - Goodbye Horses by Q Lazarus finally makes its game debut. Not being tied to one specific era has meant the sound designers have gone to town and selected music from Miles Davis through to Deadmau5. It's up to you to have your own personal 'moments' but so far we've enjoyed crawling the streets of the posher parts of Algonquin in the driving rain to the ponderous shuffle of Jazz Nation Radio, speeding down Plumbers Skyway in Alderney with Oxygene No.4 by Jean Michel Jarre at sunset and cruising through the neon-lit Times Square to the handbag disco sounds of Gino Soccio's Dancer.