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