Here is the full list of all 39 Opus Castle achievements.
Achieve all achievements
Drink until fall
Get run over
Final Office Room
See the pictures of the office
Collect the Gun
Find pin 3 of the key
Go to the entrance
Ending Room of Álvaro
Get a drink
See the photo of Alvaro's bedroom
Take a deep breath with the cigarette
Enter Alvaro's bedroom
Final Suit
Steal the jewels
Open the drawers
See the photo of the suit
Collect the pot of mugwort
Enter the suite
Find pin 2 of the key
Check up the stairs
Take a look around on the town
Collect the invocation tape
Ending Dinner room
Interact with 7 verifiable items
Eat a little
Enter the dinner room
Find pin 1 of the key
Change the cell phone's wallpaper
Access the company's app
Interact with 3 verifiable items
See the photo of the hall
Interact with the mirror
Collect the cassette player
Collect 3 items
Use your cell phone flashlight
Find the base key
Play with the goat
Try to run