Grand Theft Auto IV/Features

GTA IV is powered by RAGE (Rockstar Advanced Game Engine), with a Euphoria, Endorphin physics engine created by NaturalMotion. The core technology is the Dynamic Motion Synthesis (DMS) system. This new physics engine gives characters a "central nervous system" allowing more natural, unscripted movements. It also adds weight to each characters footsteps and causes them to transition depending on their surroundings. This is apparent when characters walk up and down stairs; instead of moving like the stairs are a flat surface, the stance of the character changes depending on if they are moving up or down. Characters react realistically to being hit with gunfire, cars, and melee weapons or fists. Falling/thrown characters will react as in real life. They won't simply be limp, lifeless ragdolls. Nor will they use a canned "super hero" animation like before. Players are also able to push people out of the way, rather than "floating" past them as in older games.

New sunlight and weather effects give the city a whole different appearance as the time of day progresses. Volumetric lighting effects allow sunlight to stream realistically into dusty interiors. Police spotlights also benefit from this effect when helicopters kick up debris. In cars, you can see real reflections on the rear- and side-view mirrors.

Animations are created on the fly, so each player's experience will be unique. Gamers are no longer subjected to prerecorded animations.

Although the size of the map is no bigger than San Andreas, the detail of the city has been enriched to a unique depth. There is no "wasted" open space, and every inch of the city tells a story.

Normal (bump) maps provide much more detail in models than the underlying polygons, as well as giving materials more texture and depth. Road and building textures are more varied than in previous GTAs. On some roads you will find potholes or metal plates where the road has been dug up. Modern pixel shaders give water, glass, cars, etc., more realistic reflections and shininess than the earlier games.

When it comes to game-mechanics, GTA IV has little in common with San Andreas. Many of the silly, unrealistic weapons have been sacrificed for the sake of realism. Players are not be able to mow down cars with the Minigun or the Radar-guided Missile Launcher anymore.

Airplanes have been sacrificed as well, which makes sense as there is only one airport; however, aerial transport is still found in the shape of helicopters. The lack of airplanes is also rumored to be because of Rockstar not wanting a reenactment of the events of 9/11 in the game, as GTAIV takes place in a recreation of New York. The driving model has also been strongly tweaked, giving a very strong sense of realism. Cars no longer feel as if they are gliding on rails. Every shake of the steering wheel or bump in the road now has very realistic feedback. Moreover, players do not find the odd, plaid parachute anymore.

The new cover system, which gives Niko the ability to duck behind walls, cars and barrels, is almost completely taken from the cover system featured in Gears of War, but then they say "if you copy, copy from the best". It makes firefights much more realistic and dramatic than the "duck and run" tactics that CJ, the protagonist of the previous Grand Theft Auto: San Andreas, had to rely on.