Kafka uses the extended metaphor of the metamorphosis throughout the novel as a way to describe change. This is seen in the literal metamorphosis of Gregor, but also in the more figurative metamorphoses undergone by the Samsa family, more specifically in Grete. For example, Kafka uses diction such as "blossomed", "shapely", and "young body" to describe the physical attributes resulting from Grete's "metamorphosis" into a young woman (55). The metamorphosis in tone after the climax of the novel (Gregor's death) is seen in how Gregor's father throws the tenants out of the house and the family goes out to the country in a car "filled with warm sunshine" contrasting to the gloom of the house they were forced to share with Gregor in bug-form (55).
A major symbol of the novel is that of the window in Gregor's room which represents freedom. Although he is kept in isolation, Gregor feels a sense of connection to the outside world when he looks out of his window. Whenever he is alone, he goes to the window and looks out at the world he is no longer a part of. Grete seems "to notice that his armchair was standing by the window...[and] push the chair back to the same place by the window" (28). This act of kindness on Grete's part shows that she encourages Gregor to feel appreciated and connected to the outside world (the window) because she still thinks of the bug as her brother. She wants him to feel free, even as he is kept in captivity, a very human response.
Once Gregor's transformation is out in the open, he loses his identity in the eyes of his family. For instance he is referred to as "it" on most occasions. The best example is when the cleaning lady tells the Samsas that she has gotten rid of his dead body by saying "you don't have to worry about the stuff next door...it's already been taken care of" (54). Basically, the harsh reality of Gregor's death is softened by referring to his corpse as "the stuff next door" which is most definitely a lighter term.
Kafka opens the story with diction of dread. This is alluded to with such word choices as “grueling”, “upset”, “torture”, “worrying”, and “miserable" (3-4). This sets the mood for the rest of the story, establishing the hopelessness of Gregor's situation (both through context referring to his human life and current bug-form) and the sheer pessimism that dominates the novel.