Just beat the game on Normal - 7 hrs. 47 minutes.
I have to say this is a step back from the original Crysis/Warhead imo. The sense of freedom that defined the series just isn't there anymore. A few levels invoked the same feeling, but overall it felt very linear to me. In the original you had sub-objectives you could complete (often taking you far off the main path), which were fun little diversions that added to the story/atmosphere. I enjoyed this exploration in the original - I was hoping to be able to run all over NYC in Crysis 2, but that's not the case.
I also liked the strategic nature of the suit in the original - having to carefully regulate each power separately added a lot of depth to the gameplay. That being said, actual combat is a lot more fun in Crysis 2 and I totally felt like a supersoldier. Which is good, because in the original it was preferable to avoid combat altogether. When the bullets start flying in Crysis 2, it's a total rush.
The story is complete garbage, sorry to say. I have no idea what happened. Which sucks because I really liked how it was presented in the original (not that it was Oscar-worthy or anything).
Technically, the game runs way better and looks really good (I still prefer Warhead's graphics though). The A.I. is very hit or miss, and I ran into a number of bugs like the melee glitch. Nothing serious or game breaking.
Overall, I think Crysis 2 is a great game it just didn't wow me like its predecessors. Especially the end game - both Crysis and Warhead had awesome set pieces that Crysis 2 doesn't even remotely touch. Still, I'm looking forward to my Post-Human run.