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