Science fiction done well is expensive, and therefore relatively rare. However, there are a ton of lower budget science fiction movies that attempt to entertain us, but few of them are great. There are certain methods these films use to make up for the lack of budget, because they have to fill up two hours, so certain plot elements and story are stretched out leaving the audience hanging on waiting for something interesting to happen. Whereas great movies might have a large number of interesting plot elements, the lower budget films might have just one or two.
You can see the similarity of many movies like this. They create a mystery to be solved, or a journey to be taken, or a horror to be fought. Somewhere along the way there will be some eye candy to please the audience, possibly some gross out special effects, and the ending might feel premature, leaving you hanging wanting to know more. All these things describe the movie Annihilation, and I'm not sure that you need to know more than that. This combination of elements, along with the all female main cast, almost works, but it leaves me expecting something better. The film tries to be original, but I spot a dozen ideas that I have seen elsewhere.
Around 25 years ago I read a short story about an alien blight that lands on Earth and slowly begins to take over more land. Within the infected area, earthly creatures mutate and become new versions of plants and animals. This is essentially the story of Annihilation. The infected area is covered by a "shimmer" and everyone who has ventured into the shimmer has failed to return. As a result, a group of women volunteers, mostly military, agree to enter to see what they can find out. It turns out that most of these women are broken in one way or another, so they all have their own motivation for taking the trip. One has cancer and sees this as a suicide mission. One lost her husband in the shimmer and wants to find out what happened.
There is nothing wrong with Natalie Portman's performance, but she once had a unique look that is not very apparent in this movie. She looks more ordinary, and age might be a factor. Oscar Isaac is a good actor, but his part here is relatively small and his dialogue intentionally bland, so it doesn't give him much to work with.
The movie is entertaining, but barely so. Movies like this keep you in suspense wanting to know how they turn out, but once you watch them there is no reason to repeat the experience.
Rating: B- . My favorite movie critic, Richard Roeper, gives Annihilation four stars, describing the movie as innovative, but I think that the film reeks of a low budget.