My play session was 9 hours. I'm pretty sure that 1 hour of that was paused (meals, family social, etc.) I completed all research entries during the completion of the main story (for 100% paythrough.) So 8 hours from MrMuggles seems very near to my experience.

There are some minor annoyances with the UI, and especially with the scripted dialog having an unpausable expiration timer. You'll likely miss a few things in your effort to avoid dying, but until near the end of the story things are never truly dangerous.

I found the atmosphere, music and story compelling.