NEW YORK — You can't get fat anymore. You can take a taxi anywhere on the map. There may be bums lying in front of a car on the street. And, for once, someone other than you might be getting chased by the police.

These are just a few of the details we soaked in Tuesday afternoon during a private 90-minute demonstration of "Grand Theft Auto IV" at developer Rockstar Games' headquarters in downtown Manhattan.

After shooing a black cat from Rockstar's game-demonstration lounge, a company employee sat on a big couch, turned on an Xbox 360 development kit and large flat-screen TV, and played three "GTA" missions set in the game's massive New York replica, Liberty City. The game looked as good as it does in its trailers, with advanced lighting, and a special physics system that makes characters walk, fall and leap in natural and often distinct ways. It had short load times; slightly out-of-sync lip-syncing, which is still getting polished; a line of sight that made buildings 10 blocks away viewable; and a bounty of unexpected visual and gameplay details.

"We just want to get you excited about the game," the third man in the room, Rockstar Games Vice President of Product Development Jeronimo Barrera, told MTV News. He said this game was immense, guaranteed to keep players busy for a long time and promised that its release would be the biggest entertainment event of the year. But mostly, he let the demonstration of the game do the talking. Several times he referred to the game as a "reinvention" of "GTA," and what was displayed demonstrated an exceptional attention to detail and an apparent effort by the developer to address every one of "GTA" players' complaints about the series' deficiencies.

The missions Rockstar demonstrated were typical of the series. They began with the new game's protagonist, Niko — an immigrant newly arrived to the big city and in search of the American dream — visiting people who want him to kill other people. "GTA" is still about crime life. Perpetrating those crimes, however, has changed. Consider the simple need to get from point A to point B. As in past games, players can steal any car. Unlike past games, they can, at any time, press a button to hail a taxi or call for car service that, for a fee, will take them to any point the player selects on the game's map.

The Rockstar demonstration of this feature had Niko waving down a yellow cab. Niko got in and the game switched to a first-person view. The cabbie turned around in his seat to ask for a destination and then started driving. Niko could pay the driver extra to ignore traffic laws and drive recklessly, or pay even more to skip the taxi sequence and jump straight to the destination. During the drive, the player can watch Liberty City pass by or switch the camera view to watch the car from the exterior. To a non-"GTA" player, this new system may seem like a trifle. To experienced players, it's big.

Other news about travel in "GTA" includes the breakthrough that cars that Niko steals now have GPS systems. A yellow route will be drawn on the player's mini-map in the lower-left-hand corner of the screen to get them to a selected destination. Players that steal luxury cars will discover that the GPS in those vehicles can talk.

The police system has been changed. Previous "GTA" games always showed a "wanted" meter in the upper-right corner. This showed how much trouble the player was in with the law, based on a number of stars. The stars only went away if the player went into hiding or was taken down by the law. The new game doesn't have a persistent "wanted" meter. Instead, crimes cause no change in the player's notoriety unless they are witnessed by a nearby police officer.

Characters still went running for cover when the Rockstar rep had Niko open fire on a truck in a crowded street, but it took awhile for a police officer to show up and give chase. Once a police officer does show up, the wanted stars pop up. What's new is that a circle flashes on the player's mini-map. This represents the part of the city where Niko is in trouble. If he can get out of it, he's out of trouble. If he doesn't split, he's going to get hunted down. And if he fights the cops, that circle is going to get bigger, making escape more difficult. In previous "GTA" games, Barrera said, "It was, 'I can commit a crime, and I just stop and hide.' But now if you do that, you'll stay wanted. [The new system] keeps you on the move."

New systems are fine, but the thing that "GTA" gamers hammer the series for is an often-unreliable targeting system. "GTA" games require lots of shooting but seldom provide controls that win any cheers. The system has been overhauled for "GTA IV." Using the Xbox 360 controller, the Rockstar rep playing the game showed that during a shootout, the player can pull the 360's left-analog trigger for a zoomed-in "free-aim" mode. That puts Niko to the left of the screen with his gun pointed at his enemies, à la "Resident Evil 4" and "Gears of War." Pulling the left trigger all the way locks the gun's sights on the nearest enemy. During a lock-on, the controller's right thumb stick can be used to target legs, torso or head. Flicking the stick left or right switches targets. Pushing the right stick directly into the controller allows for an even more zoomed-in perspective. None of this is new to games, but like the new one-button "Gears of War"-style cover system "GTA IV" has, it is a sign that Rockstar is learning from the proven control schemes of other games to remedy some longstanding issues. (The reps were proud of a blind-fire option that enabled Niko to fire a rocket-propelled grenade at a bunch of shady dockworkers while still keeping cover behind a wall.)

So much can be expressed in a 90-minute demo. The Rockstar team demonstrated the game's new dynamic car chases, which weave in scripted events that are triggered if certain situations align. For instance, during a hot pursuit past the Liberty City airport, Niko had to dodge barrels that came tumbling out of a swerving van. Other special events not shown but mentioned by Rockstar include a gas tanker driving into a gas station, or a completely unrelated car chase involving other crooks and cops whizzing by. These events won't happen in completely predictable ways, and players won't see them every time.

Rockstar showed the ability to get drunk. This made Niko's walking and driving controls wobbly and the camera so shaky that MTV News quickly asked to move on to the next feature. Niko has a cell phone and can go to Internet cafes to search the Web. Stealing a police car provides access to a police computer that can be used to find suspects. The developers talked about enemies playing dead. They showed bums lying on the street. They talked about a feature that will ensure that when a player repeats a mission, some of the dialogue may be different to keep players from getting bored. And they said that if a player fails a mission then, for once in a "GTA" game, they can press a button to warp right back to where the mission started instead of having to drive back to the beginning point on their own.

Some things were left out. The Rockstar developers did not show multiplayer. They didn't show anything romantic. They skipped the series' familiar clothes-customization features, though Barerra said players will have a less eccentric range of options. You can no longer get fat if you eat a lot of food. And you can't dress silly. "You can't have cowboy hats and pink Mohawks," he said. "That's not the mood of this game."

There is no updated release for the game. Rockstar's publisher, Take Two, has slated the game, once scheduled for October, to the company's second financial quarter, which runs from February to April. Barrera said that's still the plan, and the game certainly looks like it's going to be ready for that time frame. PlayStation 3 and Xbox 360 versions are steaming ahead, and at least the 360 version appears to be shining with polish — which isn't to say Rockstar is averse to further tweaking. At one point during the demo, Niko was getting a briefing for a mission while standing outside. It was raining during the scene, but neither Niko nor his buddies were flinching. "It shouldn't rain in this mission," Barrera said. It didn't look right to him. He sent an e-mail. It's going to get changed.