Annihilation succeeded in creating a wonderful mystery and, to my opinion, like so many times before it in the history of storytelling, crash-landed as it felt compelled to solve it. Pace, tone, character design, a little bit of side stories (smart use of cheating-story to add dread and guilt), beautiful camera and fresh production design ideas lifted the expectation to wonderful heights. The Tarkovskian quotes brought a nice touch, visiting an American Zone was funny to say the least, plus the Solaris-type metamorphosis & love story.
The CGI showers of the end killed the imagined by bringing solid form. The silly eye flickering of the end felt like a producer imposed choice.
Later edit and shout-out to the awesome gruesomeness of the animal talking help me scene. Should never forget that a film is a sum of parts, some inspired, some less so.