Yes the floaty fish friend is completely procedurally animated through code and so is the player character.
Usually when I do a game jam I try to fit a mechanic to the theme, but this time I wanted to try to build the game around the design philosophy "less is more" / "design by subtraction". I tried to use as little as possible to tell a short story, so the first half is dark and you're always going down, then it switches to being colourful and bright as you return to the surface. I guess I tried to use as little as I could to show the characters relationships