This movie was completed in 2007, and was initially scheduled for an American release in August 2008, but was delayed twice before its final release date on October 1, 2010, three years after completing production.
Chloë Grace Moretz and Isabelle Fuhrman were considered for the part of Lilith Sullivan. Coincidently, this movie opened in the United States the same week as Let Me In (2010), which featured Moretz.
This movie was released in New Zealand first on August 13, 2009, and it didn't get an American theatrical release for another year.
The American trailer features several unused scenes in which Lilith is characterized very differently.
Christian Alvart: [mirror shot] (at around 52 mins) As Doug (Bradley Cooper) pulls hornets out of his right ear with a cotton swab, Doug is reflected by three mirrors, effectively showing him four times from all angles (and the hornets as well).