For me, Flow's greatest strength was the complete lack of voiceovers, almost like a silent film. No overbearing narrator coercing you. Flow allows you to feel on your own terms without interference.

With most media since the dawn of Hollywood, the internet and now AI, we are accustomed to being told exactly what is happening. Think about how 'laugh tracks' tell you to laugh. The search for an answer or meaning of something is largely taken away from you. Without that instruction you are left to make your own interpretation of things, no delivery of a specific message or theme. This means the movie is experienced differently by everyone. That why it's so great.