• The preview was based on the PlayStation 3 version of the game. This is the first time (as far as we are aware) that the PS3 version has been previewed by the gaming press.
• The faster you tap X, the faster Niko runs. He doesn't appear to get tired.
• Major collisions on motorbikes cause the helmet to fall off. You can see it fall onto the ground.
• Heavy fire will scar - and permanently destroy - parts of the environment.
• They previewed a mission called "To Live and Die in Alderney," which is the second part of "Truck Hustle." The second mission is called "Jamaican Heat," and acts as a tutorial for the new cover/targeting system. The third mission is called "Jacob's Ladder," and the fourth (and final) mission is called "Harbouring a Grudge." This mission introduces an Irish character called Patrick McReary, who is related to Francis.
• The mobile phone can be used to call the police, the paramedics, and the fire department.
• There are 18 radio stations in GTA IV - one of which is Russian. All of these stations can be accessed via the mobile phone.
• You can take photos with the mobile phone and upload them to the police computer.
• Health is represented by a green semi-circle on the left side of the radar, and a right semi-circle represents armour. You can restore health by resting, by using medical kits, and by eating.
• In taxis, you can ask the driver to change the radio station by pressing D-pad left or right.
• The GTA 4 equivalent of the Lincoln Tunnel is known as the Booth Tunnel.

The known facts above have been added to our 10th known facts page!

Thanks to GTA4.net for the bullet points