Film reviews can be useful sources, especially for more recent films that have not yet been examined in scholarly articles and books.
Nexis Uni and Factiva
These two databases of newspapers and other news sources include articles from the 1970s until today. For older reviews, use the historical New York Times and other newspapers from ProQuest Historical Newspapers.
You can also find reviews by doing a HOLLIS 'Everything' search for Title of Film review -- e.g., Memento review or Eternal sunshine of the spotless mind review.