12

I own:

1. Secrets Can Kill Remastered
2. Stay Tuned For Danger
3. Message In A Haunted Mansion
4. Treasure In The Royal Tower
5. The Final Scene
6. Secret Of The Scarlet Hand
7. Ghost Dogs Of Moon Lake
8. The Haunted Carousel
9. Danger On Deception Island
10. The Secret Of Shadow Ranch
11. The Curse Of Blackmoor Manor
12. The Secret Of The Old Clock
13. Last Train To Blue Moon Canyon
14. Danger By Design

I own (continued):

16. The White Wolf Of Icicle Creek (PC and Wii)
17. The Legend Of The Crystal Skull
19. The Haunting Of Castle Malloy
20. Ransom Of The Seven Ships
21. Warnings At Waverly Academy
22. Trail Of The Twister
24. The Captive Curse
25. Alibi In Ashes
28. Ghost Of Thornton Hall
29. The Silent Spy

The only games I don't own:

1. Secrets Can Kill Original
15. The Creature Of Kapu Cave
18. The Phantom Of Venice
23. Shadow At The Water's Edge
26. Tomb Of The Lost Queen
27. The Deadly Device
30. The Shattered Medallion (It's not available yet)

I have completed:

1. Secrets Can Kill Remastered
3. Message In A Haunted Mansion
4. Treasure In The Royal Tower
5. The Final Scene
6. Secret Of The Scarlet Hand
7. Ghost Dogs Of Moon Lake
9. Danger On Deception Island
10. The Secret Of Shadow Ranch
13. Last Train To Blue Moon Canyon
14. Danger By Design
21. Warnings At Waverly Academy
22. Trail Of The Twister
24. The Captive Curse
25. Alibi In Ashes
28. Ghost Of Thornton Hall
29. The Silent Spy

I own #2 Stay Tuned For Danger but due to disc incompatibility issues with my newer computer, I can't play it.
I own #8 The Haunted Carousel but can't move past the Barnacle Blast arcade game.
I own #11 The Curse Of Blackmoor Manor but can't move past the key mold puzzle at the end.
I own #12 The Secret Of The Old Clock but can't move past the sewing puzzle near the end.
I own #16 The White Wolf Of Icicle Creek and have finally shoveled the pond successfully for the first time.
I own #17 The Legend Of The Crystal Skull but am stuck on the Buzzards statues.
I own #19 The Haunting Of Castle Malloy but am stuck on getting past the bog.
I own #20 Ransom Of The Seven Ships but am stuck at climbing past the monkeys.