1.) Shark - swim out far enough and jaws will eat you
2.) Explosions - gather all red barrels, and cars into a shack and toss one grenade. Kaboom
3.) Out of Map - there are some ledges or spots that allows you to reach certain areas you weren't meant to reach, and boy are they a beauty. Lots of tutorials on YouTube
4.) shoot down palm trees. It is always fun to chop down a palm tree inch by inch
5.) go back to explore the intro in daylight. When you first land on the island, it's dark. But after you go into the villages in the daytime, you can go all the way back and it'll be daylight where you foray landed, and it's beautiful
6.) hunting. Take out your rpg and shoot the adorable little beach birds
7.) Hand only Runthrough. Play the game using only your fist, punch your way through enemies.
LOL. I love Crysis for it's extra ridiculous stuff to do.
I gathered up nearly every object in the camp at the beginning of "Awakening". Set all of it next to/on top of the giant explosive container and blew it up. My frame rate seriously dropped to like 5 FPS but it was totally worth it. All the objects went flying, setting off landmines and all. lol.
I also love shooting palm trees. No idea why. Even in Crysis 2, with very few destructible trees, I shot those over, too.
Have not tried setting C4 on a palm tree yet. Will definitely try that.
I can't help but feel that this game should have had some kind of sandbox mode. Not the full PC editor suite. More something along the lines of Key To The City mode in Crackdown. Achievements would be disabled, but you want to spawn a tank? Go for it. Barrels? Sure. Chicken swarms? Absolutely. I'm done achievement-wise with the game, and will dip into it now and then for fun, and a full playthrough when I finally get a 3DTV, but the lifespan could have been increased dramatically with this addition.