And I can confidently state that without 005, there would be no Metal Gear. There would be no Tenchu: Stealth Assassins. There would be no Splinter Cell. Everything that relies on vision cones as a game mechanic traces itself back to 005.
I don't really buy this statement. If 005 could independently invent stealth mechanics, why couldn't other games invent them also? If this game didn't exist, some other game would have eventually done it.