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.
Kill 100 Pair (Grey) enemies.
Die at least 200 times.
Kill 100 enemies using the Silverballers.
Get pushed 100 steps.
Kill 100 Turning (Teal) enemies.
Complete all objectives in the fourth chapter.
Complete all objectives in all chapters without using a single hint.
Complete all objectives in the St. Petersburg Stakeout Chapter.
Complete all objectives in the sixth chapter.
Crush three enemies under a falling statue.
Complete all objectives in the third box.
Complete all objectives in the opera chapter.
Kill 100 Patrol (Yellow) enemies.
Play for at least 5,000 turns.
Get chased by three guard dogs simultaneously.
Complete all objectives in the second box.
Kill 100 Static (Blue) enemies.
Used a hint, ignored the instructions but finished the level...
Play for at least 100 turns in a single level.
Kill 5 enemies at once.
Complete all objectives in the first box.
Worn all three disguise types.
Killed an enemy by emerging from a Secret Passage.
Play for at least 1,000 turns.
Killed 2 enemies at once.
Throw an object without alerting anyone.