I was considering this question, and a friend of mind gave me what I thought was pretty good advice: if it's a young kind where you're not sure if they'll be anxious and you are more concerned about that than "spoilers", you can let them sit through a walkthrough on
YouTube with a grown-up and ask questions, while the grown-up watches their reaction to see if it makes them nervous. If it's a kid that you think might be scared, seeing a video ahead of time is not just a good test, but also a way to expose them to some of the things that might be surprising in a terrifying way, and you can prepare them for it in a way that allows them to enjoy it. They can internalize ahead of time that it's not real danger, that it has a happy ending, and that it's fun. For some kids, that might make for a better experience.