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