Perfect Stealth: Metal Gear Solid 4 - The Boss Extreme (No Detection, No Kills) 

The video covers the following parts from Act 1: Liquid Sun
1. Red Zone NW Sector
2. Red Zone
3. Militia Safe House
The Boss Extreme Difficulty
No detection, no kills, no suspicion & no alerts.
Metal Gear Solid 4: Guns of the Patriots is a 2008 action-adventure stealth video game developed and published by Konami for the PlayStation 3. It is the sixth Metal Gear game directed by Hideo Kojima