https://www.youtube.com/watch?v=5zhS4DuML5Q
The original Operation Flashpoint did a good job of making you feel like you were part of not just a mission, but a war. ArmA II, from the same developers, looks set to do an incredible job.
https://kotaku.com/arma-ii-pushed-up-a-week-5259606
Those aren’t scripted sequences. Or cutscenes. Or background objects. That battle going on involves hundreds and hundreds of AI soldiers going about their business, and you’re just along for the ride.