A beautifully animated and incredibly trippy ride. I was completely convinced, leaving the cinema, that this was a Christian parable, what with the cataclysmic flood, the animal-based "raft"/"ark", and the ascension of the "kindest" character (who just so happened to have been basically crucified by its own kind, breaking its wings) via some kind of light beam to heaven. It also seemed packed with morals around the vices of greed and sloth and envy etc.
But apparently not? If you read interviews with the director (who is also basically everything else; this film has a remarkable story behind it), they're clear that the film is about fear and hope, nothing particularly religious. I don't fully buy it, but I can see how a cat's worst fear might be a global flood and enforced friendship with a dog, so sure, let's go with that.
Then again, the director also claims that the same secretary bird that definitely tries to murder/eat the cat ‒ dropped from a great height and all ‒ is the same one that later comes to rescue him, which seems at odds with what I saw, so perhaps its all a bit in flux.
Regardless, the film is stunning. For a movie with no dialogue (bar the occasional meow and squawk) it tells its story pretty darn well. And it creates a world filled with mystery and intrigue. What happened to the humans? Are they even humans, given the bizarre whale-like, yet clearly alien, creatures? Is this some kind of ark for the species left on Earth, which would explain the strange mixture of species? We never really get any answers, and that somehow feels more fitting than the alternative.