Here is the full list of all 35 Fallout Shelter achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Successfully complete 50 Room Rushes
Scrap 500 items
Collect 20 Legendary outfits
Complete 100 objectives
Level up a Dweller to level 25
Build 50 rooms
Make 25 Dialogue Choices in Quests
Kill 10 Quest Bosses
Complete 10 Quests
Complete 30 Quests
Craft 10 Weapons
Make 25 babies
Craft an Outfit, a Weapon and a Theme
Kill 500 enemies on Quests
Successfully stop 50 Raider Attacks
Collect all Pieces of 1 Theme
Collect all Pieces of 4 Themes
Craft 1 of every room theme
Build 1 of every room type
Craft 10 Outfits
Collect 20 Legendary Dwellers
Collect 100 Stimpacks and 100 Radaway on Quests
Collect 20 Legendary weapons
Level up a Dweller from 1 to Level 10
Change the appearance of 10 NPCs in the Barbershop
Upgrade 20 Rooms to Level 3
Collect 10,000 Caps
Build 25 rooms
Collect 1000 Caps
Merged 3 Food Rooms
Merged 3 Water Rooms
Merged 3 Power Rooms
Level up a Dweller to level 50
Complete 60 Quests
Complete 100 Quests