Arrival’s symbolism is exceptionally well-integrated, particularly through its visuals, possibly more so than any film before. Initially, it seems to be about humans encountering extraterrestrial life. However, viewers who think critically will realize that the beings introduced at the start aren't what they seem to be by the conclusion of the story. The movie masterfully incorporates a wealth of meaningful images and hints that are readily apparent. It’s similar to those optical illusions where initially you see scattered dots, but once your attention sharpens and you notice a specific detail, a very intricate image emerges—one that was seemingly hidden before. While watching, I wondered about the aliens' form; it doesn't quite fit with what one might expect from an advanced civilization. I struggled to understand why they looked the way they did... but then it clicked. It was truly astonishing! I’ve noticed some people trying to make sense of how the information is presented in a linear and non-linear fashion as it unfolds. That approach can certainly help you get a more complete understanding and add layers of meaning, but I believe that the core significance of this visual achievement lies with the aliens' appearance. If you understand that aspect, you’ll be like linguist Elizabeth Banks, able to unlock the story’s deeper implications.

Source on TMDB