The Master Key allows Pac-Man to open any fruit door without the required fruit.

Pac-Man World Re-Pac is based on the Japanese version of the game, so the grand score required to obtain the Master Key is 765,000 instead of 1,000,000.

Grand-score does not add-up between save files, so the target score must be obtained on a single save file; To ensure you get the most out of each level, follow this criteria:

1. Get all fruit.
2. Get all letters and win the bonus stage.
3. Kill most enemies.
4. Earn at least one 1600 ghost combo in each maze.
5. Complete the stage without dying for a 2000 point bonus.
6. Hit the Jackpot in the slot machine at least once per stage.

Of course, there is some breathing room... you don't have to be perfect.

Good luck!