Protagonists :
The main characters are quite typical: a gloomy, insecure, hyper-reflexive psychasthenic guy (Ganta), exaggeratedly suffering from learned helplessness, and his girlfriend, a cheerful, active, athletic, and carefree sanguine girl (Isaki). Despite their differences, they share a common struggle with insomnia and become members of the astronomical club. Their relationship is marked by a paradoxical dynamic where they become sleepy around each other, a mutual compliment that deepens their bond. Isaki is attracted to Ganta's stability and reliability, while Ganta is drawn to Isaki's cheerfulness and liveliness.

Secondary Characters :
The secondary characters provide a refreshing break from clichés. The mature and reasonable Tao and the eccentric geek girl Yui are particularly pleasing, adding depth and diversity to the story.

Storyline :
The narrative of "Insomnia" is somewhat chaotic. Initially, Makoto seems unsure of what and how she wants to tell the story. This results in a shift from calm, Seinen storytelling to melodramatically exaggerated shojo-style platitudes, and then to geeky meditativeness, particularly in the technical details of camera setup and shooting the night sky. This inconsistency may alienate some viewers. At times, the plot is filled with the main characters' reflections and experiences, along with short excursions into the stories of other characters, while at other times, it becomes empty and boring.

Conclusion :
In the second half, the story finds its footing as a calm, meditative Seinen romantic slice of life with a contemplative protagonist, his sweet, cheerful girlfriend, and a touch of geekiness. The narrative concludes with a successful ending, showcasing a certain personal growth in Ganta. He ultimately decides to act against his usual obedience and responsibility, rebelling against someone else's will for the sake of his girlfriend. This character development adds a satisfying depth to the story, making "Insomnia" a worthwhile read despite its initial shortcomings.