Based on Namco's Japanese-only arcade puzzler Cosmo Gang the Puzzle, Pac-Attack is similar to many block-dropping puzzle games from the time, such as Puyo Puyo.
The objective of the game is to place ghosts and blocks that are arranged in a three part L-shaped piece, so that Pac-Man, after three or more pieces (who replaces one of the parts), can eat as many ghosts as possible to try and clear up the game area. Pac-Man's directions are chosen at random between left or right, but as he goes moving on in the game area (after you place him, of course), if he bumps against a block or the "walls" of the game area, he will change his direction.
As Pac-Man eats ghosts and clear rows of blocks, the level increases, which affects the speed and gravity of the pieces one places, as well as the amount of pieces placed before Pac-Man will appear. If one is unable to fit the bottom two parts of a piece into a legal zone of the playing area, the game ends. However, by filling up a meter on the left of the screen via eating ghosts, a fairy will be summoned in place of Pac-Man. She can fit into any empty space, and can clear up to 7 rows of ghosts; all blocks that were on top of cleared ghosts will drop down accordingly.
The game also includes a Puzzle mode. It features 100 levels, in which you have to eat all ghosts with no more than 4 Pac-Men at least (the number reduces in certain levels), and, unlike the other modes, you can change Pac-Man's direction with the press of a button.