An even better example is Majora's Mask and Banjo Tooie ! Those look absolutely sick in terms of retro "styling". As an addendum I'd like to say that no you don't have to. You're free to interpret the theme in any way you like, and while MOST people will do a N64-like game (at least probably) you could have a protagonist that owns the console, have a game inspired by the mechanics of N64 games or inspired by N64 controller gamepad layout and so on. Be mindful, however, that low poly graphics ARE one of the limitations up to vote, so if this passes, you will have to do N64-type graphics.