A good example of how change can be effective in a remake of a game. While the core expertise of the 3D level design remains, the addition of each character adds more substance and replayability. This game was honestly really difficult to me as a kid and I never was able to beat the final Bowser fight and obtain many of the more 'difficult' stars, but that just made me want to play it more and more. I'm not sure if the game is 'better' than the original (especially considering I haven't actually played the original Mario 64) but there isn't much of a good reason why it COULDN'T be considered the 'definitive' version of the game, as it keeps what made the original so good and simply adds more good on top.