Just as ground-breaking as the first crytek game (FarCry)!
One of the things I like about this is that at the end of the game - it's nearly impossible to die. That may sound funny but throughout the game it's not like that, however at the end I was so interested to see what was going to happen that I wasn't wanting to fight/play as much as I wanted to find out how it ends. It seems like they did that on purpose, which is great. There still is a lot of action at the end but it's not so much worrying about killing or being killed.
Another thing I liked is that the controls are really intuitive. If you've played any first person shooter then you're set. I downloaded the game and therefore the manual was in .pdf format so obviously I didn't read it. Luckily you don't have to.
There is a time at the end where you get a new type of weapon and you can't use it when you think you should be able to (cannot lock onto anything) but as you progress you'll get a chance to use it. That was the only part I found myself searching for a control (which there is no need to as you soon find out).
The suit you use throughout the game is really fun to use. I found myself cloaked through much of the game and I don't see how you could get around that even if you wanted to - so you'll learn how to use it.
I could see this turning into an episode-type game the way they ended it. Seems that this would be a better direction to go for them as they could build smaller pieces of the game and release them faster.
I haven't played the multi-player portion of the game yet but it seems that it would be as fun as the single-player portion.
PROS:
Great graphics; great story; good voice-overs; fun tools to use (like your suit functions); smarter than average AI; lots of action; just right amount of difficulty.
CONS:
Game unstable at times (crashed probably 20 times from start to end of story) but definitely playable due to constant saving (F5);
AI, while very good, could have been better; not long enough; flying sequence of game is the only really frustrating part of the game (not intuitive and out of sync with rest of game).