There are a few places where we've avoided game lockups, but we only changed the data, so the lockups and crashes caused by the engines remain.And it's not that flying is impossible with the new graphics engine. Rather, the problem was that processors of the time were too slow to render all the detail which would have been required to make it happen. I'm pretty sure that advances in graphics cards and CPUs -- as well as advances in graphics engines -- would have allowed NWC to implement it in a game now.