Peter Labuza’s review published on Letterboxd :
Writing about movies is often a case of revelativsm. Case and point: I don't think we'd really care about Lucy if current blockbusters weren't in an era of Strained Seriousness. But as a 90s throwback jam (this is my Awesome Mix Tape), it's sensationally fun and feels genuinely crafted instead of processed. Even before the film's ludicrous premise (which doesn't matter), Besson gives us three sequences that are right out of the Mamet playbook. Character A wants this from Character B, and we examine the interactions step by step in ping pong fury. These sequences are not only edited crisply with specific beats, but they squeeze in all the necessary exposition without overloading us in a blunt manner, and of course put together with winking fun—the intercuts of the cheetah and gazelle or Choi Min-Sik emerging from the bathroom with a pair of bloody hands.
Lucy is actually a little less fun once it actually begins delivering on its premise, and I see why Davey Jenkins could call this a Laundry List of "what cool thing she could do next?" But there's also a basic logic plot being followed here, at least in the let's get Scarlett Johansson to Paris (and a justification for why she doesn't teleport or whatever), so it's a call and response type of writing: Johansson needs to accomplish X, so the answer is Q or Z or anything else fun we can think of. More potently, the fact that Johansson is so magnetic doing this (and almost choked me up during that single shot phone call—breast milk line and everything), that I'm willing to laugh and giggle along with whatever fun crazy thing is going on. Also that and the car sequence is cleanly edited together with what looks like minimal CGI (or at least the CGI is strongly integrated into the practical effects), while the other action beats, such as the corridor levitation, are also treated practically instead of relying on overused effects.
What to do with the final act's Tree of Life insanity? It's a give or take thing, but David Fear said after the screening we attended, "No one is going to say this movie didn't go far enough." I don't think Besson is trying to really make you think about time or consciousness or any of that stuff, or if he is, I think he realizes it's all kind of a bit dumb. But this is a film that's intelligent in terms of its aesthetics, and that's a rare quality these days.