Especially in her later books, "Trimmings", "S*PeRM**K*T", "Muse & Drudge", and "Sleeping with the Dictionary", Mullen frequently combines cultural critique with humor and wordplay as her poetry grapples with topics such as globalization, mass culture, consumerism, and the politics of identity. Critics, including Elisabeth Frost and Juliana Spahr, have suggested that Mullen’s poetry audience is an eclectic community of collaborative readers who share individual and collective interpretations of poems that may provoke multiple, divergent, or contradictory meanings, according to each reader’s cultural background.