It was fine but when you compare it to Garland's previous movie (Ex Machina) it isn't nearly as well executed. Annihilation had some cool ideas and great visuals, but it just felt weak in general. I think part of my hold up was the lack of believability in Natalie Portman's character and her acting, but they seemed to introduce a lot of questions about how the thing "worked" without actually answering them.

(Tessa Thomson is a plant now I guess. Did you need to physically touch the "center" of the shimmer to get a copy? If so does that mean that the twinned deer worked themselves into that cavern too (through closed doors)? Here are just some human bones hanging out on the beach. Why did Kane's grenade just kill him, but Lena's burn down /EVERYTHING/).

Ultimately, it's hard to introduce a new idea, and the prismatic alteration of DNA is a neat one, but it is also kind of a handwaving crutch for some of the fates of both people and animals just to have cool visuals.

Judging by the downvotes anyone speaking negatively about the movie is getting, I expect the same.