Here is the full list of all 25 Pac-Man and the Ghostly Adventures achievements worth 1,000 gamerscore.
Defeat 100 enemies as Metal Pac.
Defeat 300 Blue (Scared) Ghosts.
Collect at least one Arcade Token in every level.
Increase Pac's total lives to 50 or more.
Defeat 100 enemies as Granite Ball Pac.
Complete all bonus levels.
Increase Pac's maximum Health to 6.
Complete all levels of the Pineapple Tank arcade mini-game.
Complete the final level of the game.
Complete all levels of the Pacerchini arcade mini-game.
Unlock Chapter 6.
Complete all levels of the Lemon Rocket arcade mini-game.
Unlock Chapter 4.
Collect enough Globe Energy orbs to unlock the Temple of Mystery.
Unlock Chapter 5.
Complete all levels of the Cherry Copter arcade mini-game.
Collect enough Globe Energy orbs to unlock the Temple of Ice.
Unlock Chapter 3.
Defeat 100 enemies as Chameleon Pac.
Collect enough Globe Energy orbs to unlock the Temple of Slime.
Chomp 50 recycling bins over the course of the game.
Unlock Chapter 2.
Defeat 100 enemies as Fire Pac.
Complete an entire level without losing a life.
Defeat 100 enemies as Ice Pac.