For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
Gregor wakes up one morning and discovers that he's been turned into a bug. His family and acquaintances are shocked and repulsed.
Act II
The family adjusts to life with Gregor, who remains confined to his room. However, Gregor periodically escapes from his room and has to be chased back by his father.
Act III
After his last escape, Gregor dies in his room. The Samsas take the day off and celebrate with an outing in the country. Woo!