Some of the differences between "Ms. Pacman" and "Pacman" include the addition of an extra pair of warp tunnels in three of the four game mazes. Also, the mazes themselves are different from the original "Pacman" games.
In the "Ms. Pacman" games, the behavior patterns of the ghosts are different than in "Pacman," and they also include a random element in the ghosts' movements. This prevents players from memorizing the patterns the ghosts move in, making the game a bit more difficult than "Pacman."
Fruits in the game also behave differently. Rather than spawning in the center of the map, the fruits in "Ms. Pacman" bounce along the maze in a random fashion, entering and exiting from the warp tunnels in each maze. Additionally, once every fruit has been encountered, they spawn in a random fashion. This begins at the 8th round.
Changes were also made to the death animation of Ms. Pacman. Instead of folding in on herself and disappearing like Pacman, Ms. Pacman simply spins around whenever she touches a ghost. The sound effects of her dying are also changed, as are many of the other sounds in the game.
"Ms. Pacman" has a bug in its subroutines that causes the game to become unplayable after the 256th round. However, numerous other bugs appear much earlier during gameplay, making it unlikely that a player will reach the 256th round without the use of emulation.