Time for Day 2. Thank you very much for the kind words so far!
My goals for today were underwater tiles and better atmosphere, so this is what I came up with:
I also designed 2 more characters: amazonian manatee and sea dragon.
Additionally, I've finalized my decision to make it a (mini) dating sim. Pink dolphin wants to find a date for Valentine's Day and promised to keep her friend (amazonian manatee) updated. That's why I implemented this little phone system (which took me far too long to figure out):
There will be 3 female and 3 male love interests (probably).
Tomorrow I aim to design the rest of the characters and make some coral/starfish tiles to make the world more colorful.