Here is the full list of all 28 The Eyes of Ara achievements.
Complete the Tutorial
Complete Chapter 1
Complete Chapter 2
Complete Chapter 3
Complete the Epilogue
Find your first Blue Orb
Unlock the door to the Altar of Night
Collect Christopher's scattered coin collection
Find Astra's missing paintings
Reunite Alexander's lost action figures
Assemble Clementine's scattered photo album
Locate the Backer's Gallery Secret Room
Turn off all of the Radios
Read each of Christopher's journals, Clementine's scattered journal pages, and Astra's notes
Read each copy of "The Edge of Infinity" and all "Wonders of Space" posters
Read each copy of Christopher's favourite book
Read each of the Backer's Books
Find Mike's lost coin collection
Loot the treasure horde
Spend 5 minutes stargazing in the Planetarium
Discover an odd star formation using the telescope
Locate Baron Contington's Hidden Trophy Room
Locate Lady Catherine's Secret Room
Locate the Mountain Bräu Brewery
Extinguish all of the blue Jack-'o-Lanterns during the Haunted Halloween seasonal event.
Find a way into the Pumpkin Lord's Tomb during the Haunted Halloween seasonal event.
Find all of the children's letters to Santa during the Merry Mysteries seasonal event
Open the gift during the Merry Mysteries seasonal event