I went in expecting this movie to be bad, so at least I wasn't disappointed because of high expectations. Better casting would have improved this movie immensely.

I can't imagine Luc Besson envisioning the role of Valerian and saying, "You know who would be great for this role, Dane DeHaan." Maybe he went, you know type casting? Well, let's do the opposite of that. I would really like to know what he was thinking.

I mean seriously, how in hell did the people making this movie think the pale, sickly looking with the dark circles under his eyes Dane DeHaan could pull off playing a cool, witty, bad-ass action hero? He couldn't & he didn't. I fully expected him to have a nose bleed at any moment. This guy looks like a real-life young Mr. Burns from "The Simpsons". Might as well have Jim Parsons who plays Sheldon Cooper on “The Big Bang Theory” play the role. He would have been about as believable. When DeHaan first started reciting his lines in the movie, I was like, "This guy is talking like he thinks he's a bad-ass. Oh wait, this is for real. He's supposed to be the hero? WTF?" It was awful. Surely they could have found an actor with some charisma to play the lead role. Where’s this generation’s Bruce Willis? And Cara Delevingne, sure she's cute, but come on, she looks more like a high school cheerleader than a bad-ass government operative. There is just no way to buy either of them in the roles they were playing. Among all the other things, they just seem too young. There was supposed to be a romantic relationship between them yet they had zero chemistry. I couldn't feel it and ultimately it was unbelievable.

If it weren't for the stunning costumes, sets, and visuals, this film would have been a total bust.

In the end, I did manage to suspend disbelief just enough to get a modicum of enjoyment, but trust me, this was in spite of the lead actors and weak story line.

[spoiler] Question about the story. How much time was supposed to have passed between when the Pearl Princess released her consciousness into the universe and when she landed in Valerian? The Commander played by Clive Owen was in charge when Mül was destroyed so it didn’t seem like much time at all. The movie made it seem like only maybe a week passed. PLEASE REPLY IF YOU KNOW THE ANSWER. The surviving non-technical Pearl people who lived in harmony with their environment get to Alpha, quickly learn everything there is to learn, and then apparently develop a new technology of their own that no one can penetrate to hide themselves at the core. How is that even remotely believable?
Edit: After watching the movie again, I noticed that twice it mentions that the planet Mül was destroyed 30 years ago.[/spoiler]