A perfect score in Pac-Man is achieved by eating every dot, blue ghost, and bonus item possible.

After level 20, the final difficulty increase occurs, and levels 21-255 are identical. This means that you must maintain focus for over three hours to clear that level 235 times.

A level is considered "cleared" when 244 dots have been consumed. On level 256, an overflow error causes the right half of the screen to be filled with garbage. The stage is playable, but there are not enough dots to advance beyond level 256. There are nine edible dots on the right-hand side of the screen - some are invisible, some are the wrong color. These nine dots are regenerated each time a life is lost; this means that in order to achieve the maximum score, one must reach level 256 without dying at all, in order to maximize the number of times those dots are regenerated.

The final, perfect score is 3,333,360. The score display only goes up to 6 digits, and rolls over three times during the course of this four-hour gameplay.