What strategies are used to produce meaning in this film?

The whole film is packed with meaning. There are allusions to the Bible and  great works of literature throughout the film. Here are some notes:

Roy Batty - Christ-figure

Unicorn- is Deckard "real" or a replicant?

Milton's Paradise Lost- "Fiery the angels fell; deep thunder rolled around their shores; burning...." Roy Batty

Dove at the end that Roy is holding- symbol of freedom. 

Those are just a few I can think of from the top of my head.