This game is simply stunning. It is the most frightening FPS I've ever played. I've often had to take breaks from playing it to calm myself down a bit, as the atmosphere created is so immersive. The graphics are sublime; the animations and effects are horrifically beautiful and detailed. I've not noticed any slowdown in the smooth frame rate at all. I keep asking myself how all this is possible from an Xbox console?
One really excellent feature of the game is the way the joy-pad works. It has fantastic control, with feeling and precision way better than on any other FPS I've played on any console. It's also quite a long game, with roughly 40 levels to get through. Some may say it's cheating, but I like the way I can save the game whenever I want without having to reach a checkpoint - hurrah!
I reckon this game looks even better than Chronicles of Riddick, is more fun to play than Halo 2 and is scarier than Silent Hill. Perhaps it's not as strategic as Brothers in Arms, but the simple blasting action, attention to detail, claustrophobic shock horror and sublime graphics make this a top game for me.