Since you have not give any lines for criticism, I will just cite an example of a line in John Gardner's Grendel that presents an example of the use of hyperbole.
There is one situation wherein Grendel 'killed thirty men and brought him back to his lair'. This is an example of hyperbole because it is exaggerated. It would be extremely for a person to bring back 30 men by himself, thus, the indication of it being a hyperbole is evident.
