Interesting but a bit of a let down

Rating: 6/10 (13 March 2018)

Annihilation is a film that kept me interested for most of its run time. I found the first half of the film to be a little slow. It doesn't really get going until Natalie Portman and her crew venture into the shimmer. The first half could easily have been cut down by 20 minutes, but that's a minor gripe.
Once they are in the shimmer there's lots to keep you interested, although there are some daft moments, like when the mutated alligator drags one of the women under water. Portman wades in after her and somehow fights off the giant alligator and gets her friend back without either of them getting a scratch on them.
What keeps the audience interested is the clever plot device where we're told that all the answers are held in a lighthouse in the middle of the shimmer, where everything is coming from. Unfortunately when we do eventually get to the lighthouse the ending is distinctly underwhelming. It felt like the filmmakers were trying to go for a brilliant ambiguous 2001 Kubrick style ending, or even a Close Encounters type ending, so that we'll all think they're dead clever. Other reviewers have pointed out the similarities to the film Arrival. These are valid, except for one thing. Arrival has a brilliant ending. But the ending of this film is pretty "meh", hence why I've given it a 6 instead of an 8.
Oh, and the lighthouse? Yep, it's on the beach, right next to the sea. So why on earth did they spend a week travelling through dangerous swampland to get to it, when they could have just gone there in a boat??? Or walked along the beach / coastline?
There is also a bunch of scenes showing Natalie Portman's character having an affair. There is absolutely no point to these scenes (unless I missed something?). This subplot has no relevance to anything else in the movie. It feels like the resolution of this subplot was edited out in post production.
Portman holds the film together, and the other women on the mission give decent performances. Thankfully there are no Mary-Sues in this group either. Each of them has issues and flaws. But because we're shown in the first act that only Portman survives we're cheated out of caring what happens to the others. You know they're going to die so you feel nothing when it happens, which is a shame.
The effects and the ideas are mostly very interesting and there is at least some originality here. It's a refreshing change from all the big superhero blockbusters and their formulaic storylines, but feels like a missed opportunity.
Overall, it's entertaining and has some good scares and tense moments, but I won't watch it again.