I'm not sure how familiar you are with the original Pac-Man, but Pac-Man Vs. was to create a pretty accurate multiplayer version of that. As Pac-Man, you always see the entire game area on screen - in both Vs. and the original game. Thus you can run away from ghosts, or after eating the yellow dots, go after the ghosts.
The ghosts are different. In the traditional Pac-Man, they don't always go after Pac-Man when he's not invincible, and they don't always flee when he is. To reflect that, and to also make the game more fair, the ghosts in Pac-Man Vs. don't see the entire game area and don't know whether Pac-Man is invincible. As a result, the behaviour of the ghosts in Pac-Man Vs. is not too different from the original.
If the ghosts were to see everything that the Pac-Man player does, then the ghosts would always be winning relatively quickly.
