I actually found that I was more immersed in Doom 3 than Half Life 2. Maybe because I didn't find the resistance to be as sympathetic as everyone seems to think they are. When you consider that the combine annihilated all resistance in seven hours, and that the Overwatch primarily exists to ensure humanity has a place among the combine's membership as opposed to down it's ironsights, the resistance just seems to be fighting for it's own pride than for humanity's better interests. In Doom 3, you ARE Doomguy, an individual with no real name (as of the game itself) stuck on a desicrated mars station, fighting Demons, and you can apply any traits you want to him because you are him. What I'm saying is that the graphics aren't quite what some people like to yell they are and the story was enough of a disbelief breaker to me as to be less than fully immersive.