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 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 no longer able to mow down cars with the minigun or the radar-guided missile launcher anymore.
The passage of time has been decreased in GTA IV. Instead of the standard passage of time in the GTA III Era, where one second of play would elapse one minute on the in-game clock, now every two seconds of play elapses one minute. Thus, the amount of time taken to complete a full day is doubled, from 24 minutes to approximately 48 minutes.
Airplanes have been sacrificed as well, which makes sense as there is only one airport; however, helicopters still exist. The lack of airplanes is also rumored to stem from Rockstar not wanting a reenactment of the events of 9/11 in the game, as GTA IV 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.
Unlike in previous Grand Theft Auto games, cars are more realistic. The speed of the car depends on how much pressure you apply on the acceleration buttons. Instead of just simply holding down a button and the car fully accelerates, the car's have a more realistic transmission and up shift and down shift in sync. So the car shifts accordingly to rpms. Also the car automatically shifts at according rpm speeds. The cars will shift depending on how much pressure you apply to the acceleration button. You can now rev your car's engine by holding down the handbrake button and accelerating. Engine sounds depend on the rpm your at, instead of just having the basic acceleration sound and deceleration sound, the engine sound will match the rpm. Burnouts are more realistic as smoke builds up the longer you burnout. If you burn out for too long, the tires will pop from the heat. You can control the lights. The radio can be heard from outside the vehicle. And when you turn the cars suspension lifts depending on what side you turn and how hard you turn. Just like in the real world, if you crash into a car's back at the right speed, the gas tank will rupture, sparks will ignite the fuel and the car will catch fire. Now if you flip over in a vehicle, it will no longer catch on fire. If your engine is severely damaged, the engine will refuse to turn over and the car won't start. Also, you have the ability to ignite or extinguish a vehicle's engine at your leisure. This is a useful feature for parking your hard-earned rare vehicle in the parking space at the safehouse, to ensure it doesn't move anywhere, or just for that added touch of realism.
In GTA IV, there is a new damage system. When you crash into a building or an object, you will leave big cracks or bend the objects with particles coming out. Your car's damage will depend on how hard you hit an object instead of hitting an object at 1 mph and getting a huge dent on the car; the harder you slam your car into something, the more dents/damage there will be. Boats and helicopters now take damage as well. Dents and damage will appear no matter where you hit a vehicle or an object. You can even blast through a concrete pole to kill your target.