List from io9 [http://io9.com/5619137/25-classic-science-fiction-movies-that-everybody-must-watch]

• Metropolis (1927)
• Frankenstein (1931)
• ✔ The Day the Earth Stood Still (1951)
• The Man in the White Suit (1951)
• ✔ Godzilla (1954)
• Forbidden Planet (1956)
• Dr. Strangelove (1964)
• ✔ Planet of the Apes (1968)
• ✔ 2001: A Space Odyssey (1968)
• Solaris (1972)
• Close Encounters of the Third Kind (1977)
• ✔ Alien (1979)
• ✔ Star Wars: The Empire Strikes Back (1980)
• The Lathe of Heaven (1980)
• ✔ Mad Max 2: The Road Warrior (1981)
• ✔ Star Trek II: The Wrath of Khan (1982)
• ✔ Blade Runner (1982)
• ✔ E.T. (1982)
• Tron (1982)
• ✔ Back to the Future (1985)
• Brazil (1985)
• Enemy Mine (1985)
• RoboCop (1987)
• Predator (1987)
• They Live (1988)
• ✔ Akira (1988)
• ✔ Terminator 2: Judgment Day (1991)
• ✔ Jurassic Park (1993)
• Ghost in the Shell (1995)
• ✔ Twelve Monkeys (1995)
• Gattaca (1997)
• ✔ The Fifth Element (1997)
• ✔ The Matrix (1999)
• ✔ Galaxy Quest (1999)
• Primer (2004)
• ✔ The Incredibles (2004)
• ✔ The Eternal Sunshine of the Spotless Mind (2004)
• Serenity (2006)
• ✔ Children of Men (2006)
• The Host (2006)
• ✔ Wall-E (2008)
• Moon (2009)
• ✔ District 9 (2009)
• ✔ Inception (2010)
• Looper (2012)
• Her (2013)
• Predestination (2014)
• ✔ Guardians of the Galaxy (2014)
• ✔ Ex Machina (2015)
• ✔ The Martian (2015)