The development of Baby Pac-Man was not authorized by Namco, rather, it was designed and released entirely by Bally-Midway, and along with Pac-Man Plus, Jr. Pac-Man, and Professor Pac-Man which eventually led to Namco cancelling their relationship with Bally-Midway. The hybrid cabinet consists of a 13-inch video screen seated above an elevated horizontal pinball game. 10,000 units were produced, making this one of the rarest Pac-Man sequels.
As a hybrid game, Baby Pac-Man was divided into two distinct modes of play: Video and Pinball.
Play begins on the video screen, where the player controls Baby Pac-Man through a maze. Play mechanics are similar to Pac-Man in that the object is to navigate the maze while gobbling dots and avoiding ghosts. In contrast to earlier games in the series, Baby Pac-Man's maze starts with no energizers. Instead, there are two vertical chutes at the bottom edge of the screen, which suspend video play and transfer the game to the pinball table when the player travels down either of them.
The pinball section operates as a traditional pinball game in which the player hits targets with a metal ball using two button-operated flippers. The player may earn energizers, gain new fruit bonuses, and increase tunnel speed, all used in the video mode. If the player fails to keep the ball in play, the game resumes on the video screen, but with the chutes closed. The player must then either gobble all remaining dots or be caught by a ghost in order to reopen the chutes. The game ends when the player runs out of lives.
Source: Wikipedia, "Baby Pac-Man", available under the CC-BY-SA License.