The Game: As a butt-ugly fish, you maneuver around a simple undersea maze, gobbling small dots (10 points) and evading four colorful squids who can eat you on contact. In four corners of the screen, large flashing dots (50 points) enable you to turn the tables and eat the monsters for a brief period for an escalating score (200, 400, 800 and 1600 points). Periodically, assorted items appear near the center of the maze, and you can consume these for additional points as well. The squids, once eaten, return to their home base in ghost form and return to chase you anew. If cleared of dots, the maze refills and the game starts again, but just a little bit faster… (“GL”, 1981)
Memories: Journey back with us now to the first two years of the eighties, when Pac-Man ruled the coin-op video game roost, where arcade owners’ demand for the prized Pac-Man machines was high, where players’ skill at winning was increasing and their repeat business was proportionately dwindling, and everyone wanted a piece of that little yellow pie.
In one of the most blatant instances of arcade piracy, no less than three manufacturers procured Pac-Man circuit boards, copied and reprogrammed them, and began marketing altered Pac-Man clones to make a quick buck from beleaguered arcade owners around the world. (It’s worth noting that many of these pirate manufacturers were shut down and sued out of existence by Bally/Midway and Namco.)
Piranha was easily the most elaborate attempt to completely make-over Pac-Man, but was also the most disastrous of them all. Nothing was left untouched in this clone, which removed all but the outermost maze walls, turned the monsters into squids, turned the power dots into little shells, and transformed Pac-Man himself into a ravenous killer fish. Even the sounds were retooled (clumsily). But this was not an entirely successful conversion. Your Piranha has a tendency to disappear while eating dots, and somehow the changing of the maze structure to an open cage would occasionally allow the monsters, er, 
squids, to pass from one side of the screen to the other as if there was a side tunnel there. It seems as though a top-to-bottom tunnel – shades of Atari 2600 Pac-Man! – was added, at least on the maze, though it did not work.