The first thing that has to be said about Valerian And The City Of A Thousand Planets, is that for any fan of the science fiction genre – this film goes into the list of titles that are simply required viewing. Ironically at the same time it can't be said that this is a great film, because it's very deeply flawed. With apologies to Charles Dickens, the phrase "It was the best of films, it was the worst of films" could almost be applied here.
On the positives, one need look no further than the opening 15 minutes or so where the audience is introduced to the titular City of a Thousand Planets. With nearly no dialogue at all, what begins with an audience highly confused on "what the heck is a city with a thousand planets, anyway," ends with complete clarity. Beginning with the current International Space Station, additional bays and pods become attached. Then more is added. And more. Until many centuries have passed and it continues to grow, until first contact is made with aliens and they too add their compartments to the ever-growing maze. More centuries pass and eventually the station becomes so large that it threatens the Earth so massive thrusters are attached and used to launch it away from its home planet out into the universe.
The entire sequence is simple, clear, and elegant. The sequence by itself is worth the price of admission. Only a few minutes later we shift to an introduction of an alien homeworld which puts Avatar to shame both in level of beauty as well as cultural depth and design. Again, another long span of time with nearly no dialogue, but clearly expressed.
Not only is it a film to launch a thousand epic cosplays, it's an out of the box visualization of a future for humanity and the aliens that have come along to work with them which is expressed well as any other film we've had in a very long time. Sure, there are echoes of Babylon 5 in there, along with some somewhat generic "power corrupts" themes, however the way that writer, director Luc Besson has brought the imagery together harkens back to the best of early Heavy Metal and Metal Huriant.
Unfortunately the reason that it's held back from going anywhere near being greatness, is because for all the imagery and mythbuilding is top-notch, the story is desperately uneven. Hampered to a large extent by a serious miscasting in one the leads, Dane DeHaan, who plays the title character of Valerian might be 31, but he reads and looks basely old enough to drive a car. While he's supposed to be a major and a senior agent of a galaxy-wide peacekeeping force, he mostly acts like a petulant teenager. The co-star, Cara Delevingne as Laureline, comes off far better, though still feeling far too young. At least she conducts herself with more of a sense of professionalism. They are tasked to capture a creature which is unique in the universe (and which happens to cause various other parties to also want to get their hands on it).
There's also a rather awkward working relationship with far too much awkward romantic tension between Valerian and Laureline, which might have more backstory in the original comics, but with what's on screen, Valerian comes off as basically needing a firm talking to from HR about a range of harassment violations.
That said, for all of its failings in the script, and with DeHaan perhaps not have been the best of casting choices, that's all secondary for the visual experience of the opening half-hour of the film.
Yes go see it, and when you hit those moments where you think "what was Bill thinking in recommending this thing" – it's ok, I thought it at that point as well, but then it got better again.