The watch (Symbol)
When we are first introduced to Captain Vidal, we see him looking at his pocket watch and grumpily muttering about the fact that Carmen and Ofelia are 15 minutes late. In this moment, the watch represents the fact that Vidal is exacting and meticulous in his sense of time and order. It is an extension of his fascist political ideals, his fanatical insistence that everything conform to his predetermined plan.
Later on, we learn that his father also had a pocket watch, and that he smashed it when he was killed on the battlefield, so that his son would know the exact moment of his death. The watch symbolizes the way that Vidal's sense of order was passed down to him by his father, also a soldier.
Shaving (Motif)
Throughout the film, we see many images of Vidal shaving and ensuring a neat appearance. This represents his obsession and preoccupation with everything being "just so," but it also prominently features him using various threatening implements. A razor for shaving is not inherently threatening, but in the hands of the sadistic and torture-loving Vidal, it represents an implement of terror, control, and abuse.
Labyrinth (Symbol)
The labyrinth itself is symbolic throughout the movie. It symbolizes Ofelia’s desire to escape her reality and find some kind of redemption from the hardships of life, while also representing the complexity of escaping such difficult circumstances. The labyrinth symbolizes a complex and often treacherous journey, a physical manifestation of the difficulties and complications that Ofelia is facing as an adolescent.
The Chalk (Symbol)
The chalk given to Ofelia by the faun helps her create doors wherever she pleases. It symbolizes Ofelia's desire to escape from her circumstances and to find deliverance from her difficult life. It also symbolizes the way that magic and the fairy tale world she discovers empowers her to make her own opportunities and save herself, even when it appears that she has run out of options.
Key (Symbol)
When Vidal discovers that the storeroom was opened to vandals with a key, not forced open, he realizes that Mercedes has been betraying him. Thus, the duplication of the key, and the fact that she has one, represents her disloyalty and the fact that she has been working with the rebels all along.