The locks can be used to unlock the match 3 game (25 locks) and the unlimited game mode (50 locks) which allows you to find every object in each scene. You should have seen every scene by level 15, but all the scenes repeat multiple times so you have plenty of chances to find all the locks.

1. Boathouse
   
   
   
   
2. Cave
   
   
   
   
3. Front porch
   
   
   
   
4. Foyer
   
   
   
   
5. Gate
   
   
   
   
6. Garage
   
   
   
   
7. Gazebo
   
   
   
   
8. Music Room
   
   
   
   
9. Treehouse
   
   
   
   
10. Attic
    
    
    
    
11. Dollhouse
    
    
    
    
12. Grandfather Clock
    
    
    
    
13. Kitchen
    
    
    
    
14. Reading Room
    
    
    
    
15. Dining Room
    
    
    
    
16. Fireplace
    
    
    
    
17. Garden Shed
    
    
    
    
18. Study
    
    
    
    
19. Boat Wreck
    
    
    
    
20. Bookshelf
    
    
    
    
21. Mechanical Room
    
    
    
    
22. Swimming Pool
    
    
    
    
23. Campfire
    
    
    
    
24. Cellar
    
    
    
    
25. Bathroom