If you'd like to view some of those technological breakthroughs, I suggest you hit up the Crysis Media Page on Gamespot, and check out the newest video, "Crysis Official Trailer 5", added March 30th, 2007.
If you're not a big gaming geek then it might not have as much impact on you, but I was literally stunned at some of what they've been able to achieve with this engine. The potential is absolutely massive, the immersion levels are unprecedented.
The older trailers, which show more gameplay footage, were good, but didn't convince me that Crysis would be worth spending money upgrading my computer just to play. This technological video, however, is really making me think twice. And with Bioshock just around the corner... my hand may be forced.
In any case... go watch that video. It's crazy.