Success in GoldenEye depends on completing primary and optional objectives, which scale based on your chosen difficulty: James Bond Wiki : Standard difficulty with basic objectives. Secret Agent : Adds more complex objectives and tougher enemies.
As for the ISO version, it's worth noting that "GoldenEye 007" was re-released on the Wii Virtual Console in 2010, and it's also available on the Wii U Virtual Console. 007 goldeneye wii iso