The Adrenaline Vault previews Spec Ops 2: Green Berets giving a look ahead at the sequel to Zombie's Spec Ops: Rangers Lead the Way (thanks VE). Here's a quote from the preview that talks about the effort being put into creating a true-to-life simulation:

Like its predecessor, Spec Ops 2 will strive for realism. All of the weapon sounds are actual recordings of those weapons being discharged. All of the textures are taken from photos of real objects. Furthermore, the motion capture data for their soldier character animation was taken from their tactics consultant -- a former Green Beret who runs a military training school. While wearing a full pack and rifle, their consultant provided authentic motions for treading water, climbing ladders, moving, jumping, using inventory items and weapons and even animations for bullets striking different parts of his body (which was hopefully improvisation).