Hands-On: New hands-on with Metal Gear Solid 4 (page 4 of 4)
That eyepatch is really the Solid Eye. When you equip it, you gain superior perception and a motion tracker
That thin line is a simple "threat detector." It will point towards nearby enemies, even through walls.
The animation is detailed: Snake will occasionally grab at his lower back and grimace, or stretch his neck in discomfort.
These Outer Heaven troops are sinister, but are apparently all female. A hint at the Beauty & the Beast unit?