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