This game is one of the best bits of eye candy I've seen, and plays with a decent frame rate as long as you dont go crazy on the settings. I have a med-spec (at best) pc and played the game on med settings with no slow down with apps like bitlord and my virus checker in the background. Its was only at a couple of points I needed to turn every non-vital process off to prevent slowdown. People who say you need a really beefey pc to play this are the sort of person who are only happy playing a game at its max settings, and it scales very well indeed.
The story is great and keeps up a good pace. Having said that its a little short leaving you wanting more. I have played through the story mode twice and found that its most fun on the highest difficulty because on the lower difficulties its too tempting to just switch to armour mode and take everyone out .It really makes you use your nano suit on higher difficulties, which is the best part of the game. Nothing like zipping up to your enemy at high speed grabbing him by the throat and sending him flying through a wall and disapearing into the bush, great stuff. Its also very useful to be able to customise your weapons on the fly to have lasersights, sniperscopes, granade launcher etc.
Even with all the praise the game is a little short lived and I did come across a couple of game stopping glitches. The first time a played through I had no problems but the second time I had a couple of points in the game where I completed an objective and it didnt give me the next one, which would have forced me to reload the whole level if I didnt know where the exit point was to the level (which a ran to to complete the level missing 1 cut scene in the process).
But to sum up if you love your FPS gaming then this is for you and is a must play just dont expect to still be playing it in a months time (or 2 weeks time really). Think of crysis as a short lived thrill ride that will keep your eyes glued to your pc with a big smile on your face untill its all over at which point you will have to do it all over again just because you just have to because you are left wanting more story! (think halo 2 ending).... roll on the first of what is probally a seires of expansions!