Remember how in the 60s there were all sorts of bad horror films where they had the brides of the monsters and the half divorced nearly widowed spouses... Well, it's a recipe they wanted to use with Pac-Man too. One of the first clones of the game Ms. Pac-Man.
The gameplay is very familiar, but there's a story to it. Both Pacs are in the game and they have to meet and have a love story in the end. The way to make it work is to complete the levels. You'll get to watch some animated sequences in between that tell you how the shallow story unfolds.
Unlike Pac-Man the mazes through which you have to navigate change, but that's about it. It's still the same game, just with a few additions.
So if you ever wondered how so many Pac-Games came to be, the answer is simple. Pac-Man and his Ms Pac got really busy after this game and made them all :)
The game is still just as addictive as the original, but because the idea isn't original and there aren't really any improvements the game doesn't deserve more then an average score.