Movie Quiz: Add An 'S'

The Supreme Ruler of Arbitrary Land has decreed that all movie titles must begin with the letter "S". The edict applies to old movies too, so the studios slap on an "S" and rejigger the DVD packaging. What movies are these?

1. A Civil War soldier makes his way back home to his nagging wife in the Rockies.
   
2. In this Spanish-dubbed sci-fi adventure, mankind must obey their mechanical overlords.
   
3. Which is more frightening? Tiny rodents or Shannen Doherty on a shopping spree?
   
4. Secret agent in Cuba becomes bitter.
   
5. A Texas Rangers pitcher gets caught up with gamblers and conmen.