Agatha Christie - Hercule Poirot: The First Cases

*MISSABLE*

This achievement spans the entire game, and as the description says, requires you to visit every location. The good news is that, in my experience, virtually every single location is story-related and unmissable. In fact, I think they all might be, as there is evidence in every room, so I'm not sure that you can skip any locations. However, to be safe, I have listed all locations below, and what chapters they are first available in. The list is therefore in the order of when you can access each location.

I have only marked one location as missable, because it's the only one I'm not 100% sure on, but it's still in your best interest to visit every location as soon as they become available. I have also flagged this achievement as missable, just in case (better safe than sorry).

If you follow this list, you should unlock this achievement in Chapter 8, as soon as you access the Hidden Room in the house.

Prologue
 

1. Garden (starting location)
2. Main Hall, First Floor
3. Main Hall, Second Floor
4. Bedroom
5. Lounge

Main Game
 

1. Courtyard - Chapter 1 starting area, unmissable
2. Great Hall (foyer) - almost every Chapter, unmissable
3. Main Hall First Floor (upstairs from Great Hall) - almost every Chapter, unmissable
4. Jackie's Bedroom (left side of Main Hall First Floor) - available in Chapter 1, automatic and unmissable in Chapter 6
5. Butler's Pantry (first door on right side hallway of Great Hall) - Chapter 1 and Chapter 2, unmissable in both
6. Northeast Quarter (far right door in Main Hall First Floor) - Chapter 1, unmissable
7. Southeast Quarter (door just below the Northeast Quarter door) - Chapter 1, unmissable
8. Poirot's Room (left door in the Southeast Quarter) - Chapter 1, unmissable
9. Salon (large door on the left side of Grand Hall) - Chapter 2, unmissable
10. Library (large doors at the top/left of Main Hall First Floor) - Chapter 2, unmissable
11. Major's Study - Chapter 3, unmissable
12. Major's Bedroom - Chapter 3, unmissable
13. Dining Room (small door to the right of the Salon) - Chapter 5, unmissable
14. Kitchen (small door to the right inside the Dining Room) - Chapter 5 only *MISSABLE*
15. Main Hall Second Floor - Chapter 5 and on, unmissable
16. Storeroom (take the lower right hallway to the exit in Main Hall Second Floor) - Chapter 5, and unmissable in Chapter 8
17. Cassandra's Bedroom (door on back wall of Main Hall Second Floor) - Chapter 5, unmissable
18. Margeux's Bedroom - automatic during Chapter 6, unmissable
19. Angeline and Gedeon's Bedroom - automatic during Chapter 6, unmissable
20. Zakariya's Bedroom - Chapter 6, unmissable
21. Hugo's Bedroom - automatic during Chapter 6, unmissable
22. Ernesto's Bedroom - automatic during Chapter 6, unmissable
23. Staff Quarters (door at the far end of the right hallway in Main Hall First Floor) - Chapter 6, unmissable
24. Hidden Room (hidden next to the cabinet in Storeroom) - Chapter 8, unmissable