Released: 1997, Nintendo 64
GoldenEye 007 is widely considered one of the best first-person shooters ever released, introducing new concepts and tactics which revolutionized the genre.
The game has a lot of unused content that reveals that originally the game was planned to be much closer to the movie than it is now. You were supposed to race against Ourumov through the streets of St. Petersburg just like in the movie, and Xenia was intended to meet up with you on the destroyer, none of which happens in the game.
To aid in the development process, there is a debug menu hidden in the game, and the famous Citadel level which had many speculations and rumors about it. Besides that, there are many other ideas hidden in the game files, which give an insight on the game's history...