Dr. Frankenstein tackles some incredible challenges, but in his pride, he begins to feel godlike and plays God with his science. This is no thinly veiled attempt at being God, either.

First and most obviously, Victor literally tries to bring the dead back to life. This is the entire premise of the story, and Victor succeeds in creating life from death.

Later, he calls his creation "Adam," referring to the first man created by God. By saying this, he intimates that he has created a new race and a new form of life. This is the height of his prideful attempts at being God.

Finally, in his pride, he believes that his creation should feel grateful for what he has done. While he spurns and hates his monster, he believes the creature should love and thank him for his life.

Although Mary Shelley was not particularly religious, she was writing within a culture that was deeply embedded within Christian thought. Her own social milieu was also very interested in the ancient Greek gods, albeit from a literary, rather than religious, perspective. 

The first godlike feature of Victor is that he shares with the God of Genesis the act of creating a creature in his own image. In a sense, we can say that the monster is to Victor as human beings are to God. 

The next parallel we see is in Victor's relationship to knowledge. In Genesis, humans are forbidden to eat the fruit of the Tree of Knowledge, as there are certain types of knowledge that are proper to God but not mortals. In trying to attain knowledge, humans are attempting to become godlike in a way that ends badly (the expulsion of Adam and Eve from Eden, for example); Victor is also shown as a character whose quest for knowledge beyond what is proper can be understood as a failed attempt to emulate God.

Finally, the very title of the book suggests that Victor is like the Greek god Prometheus who brings humans the gift of fire. In the works of Aeschylus, Prometheus also brings humans the civilized arts and knowledge. Victor, however, unlike Prometheus, has a failure of courage and does not care for his creation in the way that the original Prometheus cared for humans. 

Mary Shelley's novel Frankenstein illuminates the problems which can arise when mankind tries to be a god (or God--from the Christian perspective). In this novel, Victor Frankenstein, the protagonist, proves to have the God-Complex.

First, Victor brings the dead back to life. While he does not bring one single human back to life, he does use multiple parts of different humans to create a new being (noted by the use of "bodies" in the following quote).

Darkness had no effect upon my fancy, and a churchyard was to me merely the receptacle of bodies deprived of life. (Chapter 4)

Secondly, Victor has created a new Adam (this idea is illustrated when the Creature states that he feels like Adam--after he...