Sound and gameplay mechanics were altered radically from the first two entries in the Pac-Man series. Instead of eating dots, Pac-Man must eat keys in order to open doors. The doors open sections of the maze that contain what in earlier games were known as "fruits" (foods such as apples and bananas, or other prizes such as Galaxian flagships), which became the basic items that must be cleared. Once all the food is eaten, the player advances to the next level, in which point value of the food is increased. In earlier levels, keys unlock nearby doors, while as the player progresses through the levels, it is more common for keys to open faraway doors. Pac-Man can enter the ghost house at any time without a key.

In addition to the original power pellets that allow Pac-Man to eat the ghosts, two "Super" pellets are available that will transform Pac-Man into Super Pac-Man for a short time. In this form, he becomes much larger, can move with increased speed when the "Super Speed" button is pressed and can eat through doors without unlocking them. He is also invulnerable to the ghosts, who appear thin and flat to convey the illusion of Super Pac-Man flying over them. However, he cannot eat them without the help of the original power-up. When Super Pac-Man is about to revert to regular Pac-Man, he flashes white. The Super power can then be prolonged by eating a power pellet or super pellet, if available.

A point bonus can be scored if Pac-Man eats a star that appears between the two center boxes while assorted symbols flash inside them. Usually, one symbol stops while the other continues until the star is eaten, a life is lost or too much time elapses. If the star is eaten when two symbols match, the bonus is 2,000 points for any match and 5,000 points if the matching symbols are the same as the level being played. Otherwise, the bonus is similar to the award for eating a ghost, which is 200, 400, 800 or 1,600 points, depending on the level. On some versions, higher levels might award the 2,000 or 5,000 points without regard to the symbols.