I'll start with the assertion that I liked and enjoyed the movie. It was maybe a little heavy on chase scenes, but overall the movie felt good. I recommend seeing it if you like Indiana Jones movies. That's what I'll say in case you here looking for a movie review.
What this post is about though is my thoughts on the artifact... and more specifically what it can do. If you haven't seen the movie yet and don't want any spoilers, you shouldn't read past this paragraph. Okay. Going to put a break in there and then get on to the stuff I want to write about.
The Dial of Destiny was thought to be able to calculate the locations of tears in time that essentially act as bridges between two spots in time. I say "spots" because "points" is too precise and these tears last minutes. All you have to do is show up at the right coordinates at either end of the tear in time, and you can pass through and as long as it's open you can pass through back and forth. The one tear we get to see in the movie happens to be up in the air and they had to fly through with planes. Here comes the biggest spoiler: The bad guy in the movie thought he'd be able to find a tear in time that leads to a point he wanted to go back to so that he could change history. But the dial was set up to figure out where to find the right place to find one particular time tear that lead back to where and when it was created. So, the bad guy failed pretty hard.
What do I want to write about then? Time travel. It's used in a lot of sci fi and fantasy. Sometimes I like it (Doctor Who for example). Sometimes I hate it (Avengers: End Game for example). In Indiana Jones and the Dial of Destiny, I like it. They don't make a big deal out of it and aren't using it to cover up lazy writing. It's just a feature in a setting where a holy relic can send ghost-like things out to kill anyone that looks at them and a priest can pull a heart from a person's chest without breaking the flesh and without killing the person... somehow. Oh, and the Holy Grail is real and is capable of keeping a person alive for centuries and healing gunshot wounds in a second.
Part of me is still unhappy because I don't think time-travel is possible except via time dilation and that's forward only. For time travel like what we see in Dial of Destiny to work, multiple points in time would have to exist at the sme time. This could be because the movie is saying that all points in time always exist simultaneously so that there's a place to travel to. I suppose you could say it's handled with multiple realities and each tear is between realities at whatever point in time they happen to be at, but the movie is about using that time travel to change history of that world... so, I'm going with the idea that all points in time exist simultaneously. And that seems implausible in reality, hence one of my dislikes of using time travel in stories. But I can accept it here because it's not used to cover lazy writing... it's used as a tool to tell a good story. And now that I have all that out of the way...
As a ruleset to govern time travel in a setting, I think I really like this one. It's severely limited. You can't just travel back and forth to and from any time you like. There are specific difficulty to predict tears that appear and no one controls them. If you predict one and can get to the place and maybe you can tell if it's moving forward or back and prepare... and if you stay longer than 10ish minutes, you're stuck there unless they also have the knowledge to predict and locate these tears... and you won't ever get back to the same spot you left from unless you're immortal and can simply live until then or the times connected are close together. And it's plausible as a natural phenomenon. Without some pretty crazy effort, this time travel is nearly useless. This might be my favorite rendition of time travel in fiction.
