The character of Crake, known in childhood as Glenn, is a genius geneticist whose plan is to create a new race of human-like creatures to replace the destructive and environmentally unfriendly Homo sapiens. Crake can be interpreted as playing god in the novel because he revels in the ability to create and destroy life. For example, when discussing extinction, he comments:

“All it takes... is the elimination of one generation. One generation of anything. Beetles, trees, microbes, scientists, speakers of French, whatever. Break the link in time between one generation and the next, and it’s game over forever.”

Crake is fixated on the apparent ease of destroying life, and his own ability to exercise control over nature. Additionally, the following exchange between Crake and Oryx shows how Crake serves as a god figure for the Crakers, the human-like creatures he creates.

“Today they asked who made them.”
“And?”
“And I told them the truth. I said it was Crake. I told them he was very clever and good.”

This exchange shows how Crake is elevated to god status among the Crakers. Between his obsession with his own ability to control who lives and who dies and his status as creator of an entire race of human-like creatures, Crake exhibits a clear desire to "play god" and control nature.