Here is the full list of all 14 Puzzler World achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Complete 10 Missing Piece Puzzles in Challenge Mode
Complete 10 Link-A-Pix Puzzles in Challenge Mode
Complete 10 Jigsaw Puzzles in Challenge Mode
Complete 10 Crossword Puzzles in Challenge Mode
Complete 10 Picture Quiz Puzzles in Challenge Mode
Complete 10 Spot The Difference Puzzles in Challenge Mode
Complete 10 Codeword Puzzles in Challenge Mode
Complete 10 Silhouette Puzzles in Challenge Mode
Complete 10 Equate Puzzles in Challenge Mode
Complete 10 Sudoku Puzzles in Challenge Mode
Complete 10 Chainletter Puzzles in Challenge Mode
Complete 10 Fitword Puzzles in Challenge Mode
Complete 10 Hangman Puzzles in Challenge Mode
Complete 10 Wordsearches in Challenge Mode