I downloaded the demo and tried it on a PC today. Not very long for a 1.8gb download. Smooth enough on medium settings (low end dual core intel, 1gb DDR2, and a 8500 DX10 card) Looks very pretty on high settings, water is probably the best I've seen.
The gameplay (when you were actually playing not just observing whatever the game wanted you to see or listening to the radio man) was good, I get the Doom3 comparisons, the game is very dark and alternates between foreboding and frantic. Seems like a very good shooter, just not revolutionary.