Metal Gear Solid 4: Guns of the Patriots/Difficulty Levels

From GameWiki

in mgs4 there are 4 different difficulty levels liquid easy solid normal big boss hard and the boss extreme higher difficulties mean more damage taken stress level on spyche go off the charts and ennemies are more in tune as in if your smoking close to them tell smell it even if your walking WALKING theyll here it but thats pretty much it oh and you weapons doe much less damage and so does cqc