Life is a Dream is the name of a 17th century play by Calderon de la Barca. Whiler there are scenes from this play in Raoul Ruiz's film it is not actually an adaptation of the play. The film begins by explaining that Ignacio Vega memorized the play and then later used it as a mnemonic device to help him remember the names of (and other important information about) 15,000 members of a political group. Later Vega was captured and he forced himself to forget both the play and the coded information he had memorized.
As the story begins Vega has returned to his hometown where he has been asked to remember the forgotten information. His efforts to do so are in vain until he happens to go to the movie theater he frequented as a child. Coincidentally, that theater is playing the exact same movies it had played twenty years earlier and somehow seeing these movies again also causes him to slowly remember the play. From this point on Ruiz's film switches between the films Vega is watching in the theater (all of which were created by Ruiz as pastiches of various genre movies), his day to day life including his experiences at the theater and with his political allies, and scenes from the play he is slowly remembering. This being a Ruiz film these three things are in no way separate from one another: sometimes Vega sees himself and his fellow moviegoers in the films he watches and sometimes the action of the films spills into the theater; eventually the same begins to happen with the play.
Ruiz's characteristic visual inventiveness is utilized to great effect in Life is a Dream. This is very much in the same vein as his other 80's work so there are many monochromatic scenes and odd juxtapositions of characters and backgrounds. Ruiz also uses this film to express some of the ideas he had recently gleaned from his academic career. The main idea here is that the subconscious mind maintains its equilibrium by creating associations between experiences and sometimes those associations are obscure while other times they are oddly coherent and appropriate. Ruiz was evidently especially interested in the study of semiotics at this time and this film is a logical result of that interest.
Life is a Dream is very often hard to follow but as usual for Ruiz the film isn't really about plot details but rather about imagery and ideas. These are so successful so often that it's easy to forgive the less successful segments of the film. If approached with the right attitude this should be a thought provoking and diverting viewing experience.