Love how open the map is and how it allows you to approach encounters from whatever angle you want. Unfortunately that's ruined by a combination of bad design choices so despite the massive freedom pre-encounter, every encounter plays out very similarly. The AI's tracking is ridiculous, even on Normal Difficulty, so you're effectively forced into an approach that boils down to: Stealth in, kill a guy or two, run out to regen, rinse and repeat. The movement feels very stiff, too, especially in regards to jump momentum. If you don't get a running start to a jump, you barely move forward.
The ending sequence, starting from the dive into the abyss, was a clusterfuck. I liked the atmosphere and the visuals, but the extremely unfair feeling deaths(fish guys dealing 75% of your health with a charge, freeze rays being able to stunlock you in certain circumstances, etc) spoil it. Another thing that was a huge bummer was the crashes, mostly right before the very end of the flying level.
Overall I was disappointed in how Crysis turned out, after a strong start the latter half let me down. I played the game across two big sessions, and the enjoyment different between the first and the second was quite large.