Big Mouth begins with a strong premise and engaging suspense, but several elements weaken the overall impact of the series. The death of the female lead feels unnecessary and does not add to the storyline. Her character was portrayed as intelligent and resilient, playing a key role in moving the "operation" forward. Her death comes across as forced and seems included primarily for shock.

After the reveal of Big Mouse’s identity, the momentum of the series declines. Although the storyline remains engaging, the initial drive diminishes and the series increasingly relies on additional plot twists to maintain viewer interest.

The ending is also rushed and overly simplistic, especially given the plotlines developed throughout the series.