Crysis' expanse and levels are no bigger then fucking Quake's. Everytime someone talks about Crysis having big levels or expanse I almost piss myself laughing.
Are you joking?
There are multiple instances of the game opening up with levels that are several square KM in size by my reckoning, and you can run nearly anywhere in them. The best level in the game, Assault, comes to mind primarily. Have you ever infiltrated the korean warships through the water? How about the very next level in the game, Onslaught, where you assault the Koreans using a bunch of tanks? The fucking demo level is bigger than anything ever shown in MGS4. Even on the more linear levels, you can see a whole bunch of island and the "linear path" you follow takes 10+ minutes to traverse on foot (sans super speed), with huge expanses of jungle being drawn in with not-insubstantial detail.
Considering we're comparing this to
Metal Gear Solid 4, I'd like some examples of the MGS4 levels that come anywhere close to having to render the number of assets or levels of the size that crysis does. MGS4 is a series of small rooms connected to each other, and it fucking loads 75% of the time you go through a door, into another small room.