Alex Garland was hired to adapt the novel Annihilation by Jeff VanderMeer. Garland has been clear to go on record as saying that the film isn't a complete recreation of the novel; instead, he chose to create an adaptation which peeked his creative interests. Garland completely creates a world with this film with new forms of life abounding. "The Shimmer" itself is as if it is a far off memory, the texture, color and movement of the anomaly reminds one of oil upon water or a bubble blown by a child. He is able to give this foreign entity a life that connects to human emotions.
Garland also ties each character together quite well using the theme of self-destruction. Each character undergoes a version of annihilation within "The Shimmer" that is based upon the dominant state of their psyche. Thus, the way each of the characters meet their end is quite different and adds flavors to the film that splay from a seemingly tight nucleus.
Mr. Garland is also able to make a statement about the well-being of soldiers in war. Though the film is science-fiction, it is very much grounded in the symbolism of "war is hell." We see this clearly with Kane and his replica, and Lena meeting the entity wearing her husband's skin could be a very real moment that couples face when one or the other, or both, have been through the trenches of hell in battle. The film, ultimately is about salvation. Lena is determined to repair her relationship with her husband and Garland shows us that she is able to kill her self-destructive behavior (symbolically with the entity in the lighthouse) in order to provide an environment that will allow them to work through the very real issues of identity that now are before them.
