The best and real spy-game ever made. Metal Gear is great but Splinter Cell has the best mechanic and it's more real.
Lights, moviments, weapons, cameras, bodies and all other peaces of this game are great because they remember the real world in the graphic aspect and funcionality.
This game have a complex playbility due the many equipament available in your missions. Weapons with attach components like sniper, cameras and others. Night, Heat and Eletromagnetic Vision Googles. Hacking instruments. This game has a complex mechanic but is not too hard to learn it, after this you understand the reason that made this game the most realistic in the genre.