Whereas Grand Theft Auto III tended to preen over its outdoor areas, GTA IV invades the great indoors, comprehensively redecorating the interiors of Liberty City cabarets, strip clubs, taxi offices, apartments, gun shops, beer gardens, bowling alleys, art galleries, and more. Cruise the city, and you'll still note a preponderance of buildings with impenetrable facades and disappointingly blurry textures with illegible text, but -- on the whole -- the sense of standing in a living city with distinctive locations and aesthetics is the strongest it has ever been in an urban simulation. You'll also spend a fair amount of time climbing around or on top of various city structures. At one point, for instance, you have to run a hair-raising rooftop gauntlet, climbing a half dozen floors within a building before popping out on top some five or six stories up. You then spring from building to building in pursuit of your quarry, and cling precariously to jutting odds and ends to survive nearly impossible leaps. Once you've completed your task, stick around for the view, especially at dawn or dusk -- the game's manipulation of lighting is so good, it's heart-stopping.