Here is the full list of all 26 Hitman GO: Definitive Edition achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Complete all objectives in the St. Petersburg Stakeout Chapter.
Complete all objectives in all chapters without using a single hint.
Kill 100 enemies using the Silverballers.
Complete all objectives in the sixth chapter.
Kill 100 Pair (Grey) enemies.
Die at least 200 times.
Kill 100 Turning (Teal) enemies.
Get pushed 100 steps.
Complete all objectives in the opera chapter.
Crush three enemies under a falling statue.
Kill 5 enemies at once.
Kill 100 Patrol (Yellow) enemies.
Complete all objectives in the fourth chapter.
Get chased by three guard dogs simultaneously.
Play for at least 5,000 turns.
Complete all objectives in the third box.
Kill 100 Static (Blue) enemies.
Used a hint, ignored the instructions but finished the level...
Complete all objectives in the second box.
Play for at least 100 turns in a single level.
Worn all three disguise types.
Killed an enemy by emerging from a Secret Passage.
Play for at least 1,000 turns.
Complete all objectives in the first box.
Throw an object without alerting anyone.
Killed 2 enemies at once.