This game is all kinds of awesome. I bought it just to check out the graphics, but, somewhat surprisingly, the FPS-on-rails gameplay actually is a lot of fun. (Note that I played it only on an iPhone.)
The graphics are utterly mind-blowing, especially when you take into account that they're being generated by a tiny computer you carry around in your pocket. The initial visual shock was not unlike the way I felt when I first played certain computer games in the mid-to-late '90s (like, for example, Turok: Dinosaur Hunter (3Dfx Voodoo anyone?)) and couldn't believe the pretty polygons were being created by my computer, and not an arcade machine.