"Flow" was a huge disappointment for me. I couldn't get past the animation jerkiness and overall unrealistic look. I have two cats, and cats simply don't move like pictured: while most of the keyframes were perfectly fine, the transitions between them were off, which completely broke it for me. Heck, "Stray" (the video game) had much more realistically moving cat than "Flow" and I think it's supposed to be the other way around. I get that it was "indie" stuff done on a relatively small budget, but those broken movements became sort of an uncanny valley for me.

I guess, I also had wrong expectations from the beginning. The movie was heavily advertised as non-verbal, so - naturally - I expected it to portray the behaviors of non-human consciousness (with slight allowances for plot reasons, sure). And then the animals behaved as if they were unquestionably and heavily anthropopsychic.

To sum it up, "animals don't move like this and don't behave like this" paired with some invalid pre-expectations, sadly, was too much to break my suspension of disbelief and ruin the movie for me.

But yeah, it's certainly not a "mindless banter in between sex and explosions".