Overblown nonsense that is only marginally entertaining.

Rating: 5/10 (5 March 2015)

Difficult one to call, this. On the one hand, the science is absolute nonsense, but it manages (just) to keep your interest to the end. I can't say I was sad when the end came, more relieved.
The worst thing about Lucy is that it takes itself entirely too seriously for a film with this much nonsense in it. I will happily ignore all kinds of BS if the movie is entertaining or pokes fun at itself, or does something clever with the silliness. Lucy does none of those things.
Instead, it tries to be a bit preachy with its humans and nature are intertwined, we only use 10 percent of our brains, blah blah blah stupidity. As a result, it comes across as too up itself.
It's a shame really, because there was a good concept in the story that just wasn't done justice to by the film.
My major issue was with the sudden onset of superpowers all tied to the increase in Lucy using her brain more. Why? How? It basically is saying that, if we learn to use our whole brain capacity, we will become gods! Which of course ignores the fact that we are still evolving and, presumably, our brains will increase in size and capacity over time. So what is special about the human brain at the precise instant in time that Lucy takes place? The answer, of course, is nothing. It's just a conceit of the storyteller to think that humans are special and that all we lack is the ability to use all of our brain in order to become masters of everything.
Lucy walks a very unsteady line between science and magic, if I'm honest, with things happening... because!... and with little attention to consistency.
Lucy herself apparently turns into a soulless automaton as the result of her "evolution" (yes, the quotes are deliberate there), making you wonder why anyone would want such an ability in the first place. She kills, she maims, she shows no regard for anybody's life. Yet we are supposed to cheer her on? It is all nonsense and has been done better in a number of other movies already. I suppose I shouldn't be surprised that Besson butchered this. It probably would have been better in the hands of Michael Bay! All in all, not worth the time unless you like frowning at the screen and saying "Why?" a lot, interspersed with plentiful numbers of confused glances with your neighbours at the inconsistency of it.
SUMMARY: Utter nonsense trying to be clever. It fails at that and also fails at being entertaining for the most part. Pseudo-science gobbledigook that is really not worth your time.