To have a easier time getting the achievements in this game: Pause the game, go to Game Settings, select 5 lives and activate Round Select, you will get the achievements with ease this way
As the name suggests, you need to clear the second maze of the game, pretty easy, 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 and the Strawberry after eating a few Pac-Dots in Round 1 and 2 respectively for a few achievements.