I played this game way back in 2004, but I am tempted to review this now as Splinter Cell's 6th version blacklist is on way soon.
The main protagonist of the game Sam Fisher of the 3rd Echelon, is the coolest stealth operative to hit the screens. With an array of gadgets, you attempt to finish your missions with stealth and precision, trying not to trigger alarms and using your pistol to break the light sources and so as to keep darkness spread uniformly.
Crouching through dark areas and sneaking up on guards to take them on and hide their bodies in dark where they wouldn't be found. This is the main USP of the game and does absolutely well with great usage of thermal and night vision goggles. From levels spread through an oil refinery, CIA head quarters, slaughter houses, Chinese embassy to presidential palaces, this game never fails to surprise and thrill. You keep going through each level in silence and stealth to accomplish your mission. Be careful not to trigger alarms, as they can end a mission.
The only other Splinter Cell to match this level of sophistication and game play replay value is Chaos Theory.