Graphics are usually not the most important feature of a game but here it's the most shining part.
A 2008 release with a 2007 engine and it looks better than anything current. While it was a bit stupid how many gamers thought Crysis ran bad on their "ancient" machines (use lower settings! then it would have looked better than most games
) it now runs perfect on average gaming rigs with really fun physics/explosions.
The nano suit doesn't work well imo, at least on the hardest level were you die fast. Speed is for running between action, never found an opportunity for use in combat, strength is pretty useless except for the jumps you have to make, cloak is fine to observe the area without getting caught instantly but for attacks the enemies were too many and it would take forever to wait for the perfect moment. So shield is in almost every moment the best choice to survive. Without it every hit can be lethal, so every attack would have to be perfect and that takes longer than rush in and die occasionally. In theory it sounds good, but in this case i think i would have preferred (again, as in Crysis) gameplay focused on "normal" shooting like in Far Cry. As it appeared to me the suit is a gimmick that lacks proper game design to offer really four gameplay styles.
AI had no bad performances this time. In Crysis sometimes they got lost in the woods, especially bad if you have to clear the area and instead of being chased i had to search them. But Warhead was imo more linear so they could not run around so far. Alien AI was also well done with the Men in Black crash landings stopping in front of your toes.
Crytek seems to need a better director. The story was ok, but this is the area were the game could have been improved the easiest. It tries to be one of those cinematic action games but we're not in the 80's anymore were this would fit good to Cobra (Die City Cobra) or Raw Deal (Der City Hai).