Some of my favourite slow-burn adventures that no one's mentioned yet:
- Project Zero/Fatal Frame (1, 2, and 3)
- Shadow of Memories/Shadow of Destiny
- Echo Night: Beyond
- Zettai Zetsumei Toshi 1 and 2 (a.k.a. S.O.S. The Final Escape/Disaster Report, and Raw Danger)
- Killer7
- Siren (1 and 2)
- Chulip
And some action-adventure-RPGs that have a place in my heart but aren't generally considered to be anything special:
- EverGrace (there's also a sequel which I haven't played yet)
- Eternal Ring