Here is the full list of all 16 Agent Walker: Secret Journey achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Complete all the uniforms.
Find and complete all collections.
Finish a Hidden Object Scene without a mistap.
Find five items in Hidden Object Puzzle in five seconds.
Destroy the Spear.
Solve all the Minigames without using Skip.
Finish all Hidden Object Puzzle without using Hint.
Find all the miniatures.
Find all the figurines.
Watch all Cutscenes without skipping.
Find three items in Hidden Object Puzzle in three seconds.
Solve three Minigames without skipping.
Solve three Minigames in less than ten minutes.
Finish a Hidden Object Puzzle without a hint.
Solve a Minigame in under a minute.
Solve a Minigame without using Skip.