Alex Garland does great work in the sci-fi genre, and some feel that he is particularly good when it comes to the movies that he has so far directed (mainly, well, Ex Machina and this). His films are smart, visually arresting, and packed with intriguing ideas. It's just a shame that this film seems a bit overstuffed and unsure of exactly what is being said.
Natalie Portman plays a biologist, Lena, who ends up on a dangerous exploratory mission when she is trying to discover what happened to her husband, Kane (Oscar Isaac), on his last military mission. She accompanies four other women through an area surrounded by "the shimmer", an unknown phenomenon that seems to mark the growing boundary of an environment fatal to almost all who enter. Everyone knows the risk, but they are all hoping to at least discover some answers before their time is up.
Based on the first book in a series by Jeff Vandermeer, Annihilation is definitely something you can see easily appealing to Garland. It's a sci-fi tale, much like Ex Machina, in which the characters are constantly trying to wind their way through areas of murky morality. What constitutes life, and what gives others the right to assert themselves as the unassailable final step in evolution? Because the shimmer causes pain and damage, yet also creates new life, often in a surprisingly rapid manner.
The material is boosted by the cast, with Portman joined by Jennifer Jason Leigh, Gina Rodriguez, Tessa Thompson, Tuva Novotny, and Isaac appearing largely in flashback scenes. All of the characters are carrying their own baggage (otherwise why go on such a mission?) and the performances match the flawed personalities.
The problems with the film don't lie with the cast, they lie with the script. Sadly. Garland seems to have been won over by the potential of the ideas here, so much so that he tries to overstuff the film, losing focus during times when he should be building a much clearer picture. The structure highlights this, with scenes that are flashbacks stuck on to other flashback scenes, and a lot of moments that don't feel like anything more than unnecessary filler.
To sum up then, Annihilation is a solid sci-fi film with a very capable cast, and one or two memorable moments, that doesn't ever become a completely satisfying work. Which was perhaps the aim of Garland, considering the core premise.
You cannot buy Annihilation at the moment, but feel free to pick up any of the other, superior, films from Alex Garland.