Their new engine pulls out every trick in the book in order to make speedy rendering of randomized levels possible. Take, for instance, your outdoor areas: the game pre-computes the localized light sources (like streetlamps or small fires). Then, during load time, the game quickly calculates the "global lighting" (like moonlight, or the demonic red glow of a burning sky) that illuminates the whole area. If it all works (and judging by our playtest, it's working great) the level will hopefully look as good as something that was pre-rendered in your standard 3D engines.
Probably the most frustrating thing about it is, if the engine coders do their job, nobody will notice that they rewrote the book on 3D game rendering. It's a hard life.
But the results are outstanding. In Hellgate: London whole cities or underground networks spontaneously appear, different every time. Like a kid with LEGO blocks, the game engine places large set-piece environments next to one another and connects them with any manner of randomized streets or corridors. Whole tenement blocks of buildings are strung together from base elements. Buildings can be turned or rotated as needed, and tons of random debris can be scattered on the roads to make every area a unique challenge. In the underground, corridors twist and turn and dead-end, snaking all around on top of one another. It's easy to get lost. Of course, it's also fun.
