What are the differences between the alternative versions of Blade Runner?

I may have lost count, but the last time I checked there were 4 different cuts of Blade Runner. The original cinema release (with the voice over and the spliced from another movie ending) followed by three different versions cut by Ridley Scott.

But what are the key differences between those versions?

Answer

Maybe this Wikipedia site is of help. To sum up the most important things:

• 1982 Original workprint (failed in audience tests, not released):

  
  
  
  
  • no voice over
  
  
  • no happy ending
  
  
  • no unicorn dream
  
  



• 1982 US theatrical release:

  
  
  
  
  • voice overs
  
  
  • happy ending (Deckard and Rachel drive through the countryside)
  
  
  • no unicorn dream
  
  



• 1982 International release:

  
  
  
  
  • more violence in certain scenes
  
  



• 1992 Director's Cut (not done by Scott, but approved by him):

  
  
  
  
  • no voice overs
  
  
  • no happy ending (Deckard and Rachel just leave Deckard's flat)
  
  
  • unicorn dream (suggesting that Deckard could be a replicant)
  
  



• 2007 Final Cut (Scott's final version):

  
  
  
  
  • same content as Director's Cut. Plus new scene Deckard at piano and outside club.
  
  
  • many technical improvements