Here is the full list of all 21 The Peanuts Movie: Snoopy's Grand Adventure achievements worth 1,000 gamerscore.
Unlocked the Flying Ace Costume
Unlocked the Masked Marvel Costume
Completed all Lunar Surface levels
Completed all Skies of Paris levels
Completed all Parisian Underground levels
Completed all Melody Chateau levels
Collected all Jelly Beans in a single level
Collected all kids objects
Unlocked the Joe Cool Costume
Unlocked the Detective Costume
Unlocked all Costumes
Found all the kids
Broke through a wall as the Masked Marvel
Completed all Temple of Bunnies levels
Unlocked the Astronaut Costume
Completed all Peppermint Jungle levels
Defeated The Mask Boss without being hit
Unlocked the Beagle Scout Costume
Jumped on three enemies without touching the ground
Level finished
As normal Snoopy hovered for more than 5 seconds