"There is one significant improvement from Doom 3, however, in that the environments are a lot more varied. Some people liked wandering around the enormous but mostly claustrophobic and very dark scientific/military complex for hours on end. I thought it got kinda monotonous after a while. Well, RoE features much more wide-open spaces, more varied locations, and just plain cooler locations. Unfortunately, I can't be too descriptive without giving away spoilers. But, for those of you who were disappointed by Doom 3's level architecture, you'll be pleasantly surprised by what RoE has to offer. It will also probably take you 12-15 hours to wind your way through it, so this is a impressive large level addition."