Why Did I Let My Kids Watch That Movie?

So here's what happened recently. My wife and I were trying to catch up on some household chores during the weekend while my kids, aged six and eight, were watching TV. They've been asking for a movie recommendation, but we wanted something that wouldn't keep them awake all night or scare them with intense action scenes. So after much deliberation, we chose 'Puss in Boots,' which seemed like it should be light-hearted enough for young kids, right? I mean, it's an animated film based on a beloved character from the Shrek series, so how could there possibly be any issues? Well, let me tell you, as soon as they started watching, I noticed that my older kid was leaning into their younger sibling with eyes wide open and whispering every few minutes. Now, this isn't unusual for them; when they're scared by something, one of them tends to reassure the other. But after about thirty minutes, things escalated. My six-year-old's whispers turned into little shrieks and my eight-year-old was just as tense as could be. I should mention that we had already told them that this movie would have some scary parts, but it seemed like those 'scary parts' weren't being described accurately in the trailers or promotional material. When I peeked at the screen myself, I was surprised, there were indeed moments of intensity and fear-inducing scenes that I hadn't expected. After about an hour into the movie, my older child ran to us with tears in their eyes and begged me to turn it off. My wife and I tried to explain that we knew this might happen but thought it was worth a shot since 'Puss in Boots' usually has positive reviews for kids. Yet here we are, feeling like the worst parents who allowed our children to be scared unnecessarily. So, my question to you all is: Am I being overly cautious? Is there really no way to predict how your child might react to certain scenes in a movie before they watch it? Or should I have been more vigilant and read reviews with an extra careful eye for potential triggers for young kids? It's one of those things that seem clear after the fact, maybe we should stick to movies our kids have seen or are specifically marketed towards their age group without any adult-like themes. What do you think? Do I need to be more conservative in future choices?