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