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