As the name suggests, you need to clear the nineth maze of the game, can be a bit tricky depending on your skills on Pac-Man, just eat all the Pac-Dots while avoiding getting caught by the ghosts, once you eat all the Pac-Dots, a small intermission cutscene will play and you'll get the achievement.
Also, make sure to eat the Cherry, Strawberry, Orange, Apple, Melon and the Galboss after eating a few Pac-Dots in Round 1, 2, 3, 4, 5, 6, 7, 8 and 9 respectively for a few achievements.
I also recommend avoiding eating ghosts so you can have some extra time to eat the Pac-Dots, 'cause if you eat them, they will regenerate and become dangerous again, only do it if they surround you. Save the Power Pellets for when you're almost done with the level, that way you have some backup for whenever you're in trouble, only use it early if it's an emergency.