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