Here is the full list of all 134 Pixel Puzzles Aardman Jigsaws achievements.
Puzzle Complete
Complete 20 Puzzles
Place 2,500 Pieces
Complete 10 Puzzle Packs
Complete 10 Puzzles
Complete 5 Puzzle Packs
Complete Your First Pack
Place 1,000 Pieces
Complete 5 Puzzles
Place 500 Pieces
Complete Your First Puzzle
Place 100 Pieces
Place Your First Piece
Puzzle Time!
Place 10,000 Pieces
Complete 50 Puzzles
Complete 100 Puzzles