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.
Find and complete all collections.
Find all the miniatures.
Complete all the uniforms.
Find five items in Hidden Object Puzzle in five seconds.
Find three items in Hidden Object Puzzle in three seconds.
Destroy the Spear.
Solve all the Minigames without using Skip.
Finish all Hidden Object Puzzle without using Hint.
Find all the figurines.
Watch all Cutscenes without skipping.
Finish a Hidden Object Scene without a mistap.
Solve three Minigames without skipping.
Solve three Minigames in less than ten minutes.
Finish a Hidden Object Puzzle without a hint.
Solve a Minigame without using Skip.
Solve a Minigame in under a minute.