Double posting because I just finished Still Wakes the Deep :P It wasn't very long, only about 4 hours apparently.
It was.. okay!
definitely more of a walking simulator kind of horror game, with a few stealth sections reminiscent of Alien: Isolation or Amnesia: The Dark Descent. I had kinda hoped it would be a little more scary, though :/
The game was EXTREMELY linear, and I definitely would have wanted to see more paths/gameplay options, especially since there's no combat. The visuals, environmental design, and story were all really good, however, and the voice acting was top notch. Every character has a strong Scottish accent, and they all put a lot of emotion into their performances. Story-wise, it definitely plays out like a horror movie - Event Horizon, Aliens, and The Thing all come to mind, if those movies took place entirely on an oil rig in the North Sea.
Overall, I liked it, and would probably give it a 7/10. It's a bit lacking as a game, but I thought it was a worthy horror experience.