I love the aesthetic, both the character portraits and map design give atmosphere and I am a sucker for retro/analog aesthetics for horror. A TALKING DOLPHIN? such a fun idea and reminds me of Johnny Mnemonic which is always a plus. There are some grammatical errors throughout and could use a quick editing polish. I was confused by the exact size of the crew as I assumed at first it was only the four NPCs on the ship but then on the room key it talks about extra crew. Not every character needs a portrait (I do think one of the alien ambassador would be really cool though) but it might help to list out the full crew even if its just a list of names and roles. I feel as if the NPCs could be fleshed out more, outside of the dolphin most of them don't give me much. Lots of really great ideas for blending of alien cultures, animal rights, and preserving/pillaging nature and I'm a sucker for anything set in a submarine. I feel like you could take the ideas further and elaborate on some of the bigger theme ideas, what's the morals of the crew? do they all think of Doris as a pet? You could use their relationship with Doris to indict what they think of nature and maybe what they would do with the talking pearl. Overall, there are the bones and threads of something really intriguing and I am interesting in bringing A TALKING DOLPHIN?!?!?! to my table. I do think I would have to do some prep work and further some of the ideas and threads you have here but overall vibes, aesthetic, and themes are headed in the right direction. I would like some alien and sea monster art as it'll look so great in the aesthetic that you crafted. I think you can get weird with some of the ideas as the central premise is a talking dolphin so some crazy sea monsters would feel at home.
Side note I am not sure if it was just a problem with my computer and how I displayed the file after downloading it but the text was unreadable when a page would fit on the screen and I would have to zoom in to be able to read. Again I am not sure if its my end or something with the file but at least something to look into.