The 2022 anime film Bubble is part adaptation of, part inspired by the Hans Christian Andersen story, and in my opinion one of the more interesting ones (and especially a non-cynical one) to use elements of the mermaid's story in a new setting.
Set in the near future, mysterious bubbles arrive on earth from space in a worldwide apocalyptic event, with the Tokyo Tower at its epicenter. Five years later, most of the world has been able to move on, but Tokyo remains filled with bubbles as well as gravitational anomalies that make it a dangerous place to live. But while most of Tokyo has been abandoned, many orphaned youths have moved into the derelict city, where they scavenge for goods and play battlekour, a competitive parkour gauntlet through the collapsing city.
One of the better battlekour players is Hibiki, a youth with audio sensitivity who is drawn to a song only he seems able to hear coming from the Tokyo Tower. One day he is rescued from drowning by a strange, quiet girl he names Uta. Uta is actually one of the space bubbles given temporary human form, and she's been watching him in secret since the arrival of her kind five years ago.
The story itself is pretty straightforward, though its adaptation of elements from The Little Mermaid are, in my opinion, clever: from the use of familiar imagery of the prince's rescue (with a twist to that rescue), to how the story incorporates the threat of the mermaid character turning to sea foam. The story is also a celebration of the fragility of life, and how we all come from the same atoms in stars and will one day return to those stars, but for a relatively brief moment in the existence of the universe, we are "us" – people who live life and love. Uta, as the symbolic mermaid, is merely a more extreme version of that same idea, and her experience as a human is joyous. The movie explicitly uses the Hans Christian Andersen text in spelling all this out, but it's still neat to have it all tied together and supported by stunning animation that depicts extreme parkour that evokes the feeling of underwater weightlessness.