Ok, before starting crysis 2, you need to know the following:
This game DOES NOT run on 10.5 or below AND is very demanding so please note that you WILL have to run it on lowest settings if you have a weak mac. Powerful macs with 4GB+ RAM, 2.60Ghz+ and a good graphics card can probably run this game on medium - high settings without Lag.
When you start up the game, an image of a 'EYE' will appear. It will stay that way for around 50-70 seconds then the game will load up. this is just the game preparing its self for startup. Sometimes, on certain resolutions, you may experience the game to 'Randomly Quit Itself' if this happens, go back onto Crysis 2 and change resolution, load the game again and after it loads, set it to the resolution you wish it to be.
This is a cider port so by holding buttons 'cmd' and 'enter/return' the game will go into windowed mode. This is useful for when you want to do something else while playing. DO NOT go into the game settings and uncheck fullscreen OR check windowed mode as this can cause the game to not show up the next time you start the game.
Enjoy.