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