- Mini-games confirmed for GTA IV include pool, basketball, darts, golfing at driving ranges and arcade games, such as Go Go Space Monkey, which was also featured in San Andreas.
- The trucking company from San Andreas, RS Haul, returns and missions based around the company have returned as well.
- 'Gruppe Sechs' securicars have returned and players are able to steal them and deliver them to locations for a reward, but this task is said to be much trickier than in previous games.
- The game features many references to 'Crackdown,' a GTA-style game available for the Xbox 360 which also uses RenderWare, GTA's previous engine.
- Vehicles such as the Stallion and Comet from previous games appear in IV, as well as the NRG500, a motorcycle. A new motorcycle called the NHG900RR is also confirmed to be in the game and is rumored to be the fastest one available.
- GTA IV contains photos of Vice City, similar to the maps found scattered around San Andreas. References to previous GTA games through graffiti is also spread throughout the city.
- Binco, Burger Shot, 24-7 and Clucking Bell are all returning, in addition to many other brands from previous GTA games. 'Alderney' features several strip malls where you can purchase food, clothing, and more.
- New York City-style news tickers on buildings will be constantly updated based on what crimes you commit in the game.
- There are several innuendos and references to the Hot Coffee mod for San Andreas.
- As previously mentioned, pedestrian actions will be incredibly varied and detailed compared to previous games.
- "Flushing Meadows (site of the NY World's Fair) is featured in its entirety, as is a recreation of theme park Astroland at Coney Island. Rides such as the Corpse Ride and Cyclone can be tested, and the major tourist spots will play a part in some missions."
- Sprunk can be purchased, as in San Andreas, to replenish your health.
- Similarly to Saints Row, yet another GTA-style sandbox game, phone numbers are scattered throughout the city and you can call them for whatever services they entail.
- A place called the Videogeddon Arcade allows you to play arcade games and posters attacking violent video games can be seen.
- The 'sky tram' featured on the box-art for GTA IV can actually be used as a mode of transportation, although it costs money as do the taxis.
Read the original list here @ ComputerAndVideoGames
Thanks to Wheelman101 for finding this.
Also, the new issue of GamePro features a preview of GTA IV's multiplayer. While the article contains no new information, three brand-new screenshots are featured in the article:
Thanks to nikolaibellic for finding these.