I have used a pretty broad definition of Science Fiction to compile this list, including movies with any kind of action not explainable by normal human agency (this accounts for the films about the occult or about psychic powers) as well as the more traditional categories of space and time travel, human/alien interaction, etc. After each title, I tried to indicate what sort of sub-field the movie belongs to, although some are pretty hard to classify. The listing also includes my star rating for each movie. As you can tell by the large proportion of 4- and 5-star movies here, I really like science fiction. Your ratings may vary.
(NOTE: Dates covered are mid-1983 through 1996. I didn't start using stars until late 1989, so ratings for movies older than that have been added after the fact. Also, I did not write as many reviews as Siskel & Ebert. These are definitely NOT the only sci/fi movies, or the best sci/fi movies, to come out during this period; they're just the ones I have reviews for.)
2010. Space travel; more of a "hard sci/fi" movie than 2001 was, but still includes some transcendent moments. 
ADVENTURES OF BUCKAROO BANZAI, THE: ACROSS THE 8TH DIMENSION. Hallucinatory fantasy. 
ALADDIN. Fantasy (wish-granting genie).
ALIEN NATION. Human/alien interaction.
ANGEL HEART. Occult (devil's bargain)
ALIENS. Human/alien interaction; space travel. 
BACK TO THE FUTURE, PART II. Time travel. (original also gets 5 stars)
BACK TO THE FUTURE, PART III. Time travel.
BATMAN (superhero)
BATMAN FOREVER (superhero)
BATMAN RETURNS (superhero)
BEAUTY AND THE BEAST. Fantasy (spells of enchantment and their reversal).
BEETLEJUICE. Occult (ghosts); fantasy.
BELIEVERS, THE. Occult (voodoo).
BIG. Fantasy (child/adult switching).
BRIDE, THE. Frankenstein spin-off.
CHRISTINE. Occult (demonic possession).
COCOON Human/alien interaction.
D.A.R.Y.L. Artificial intelligence.
DARKMAN. Superman/revenge story.
DEAD AGAIN. Occult (reincarnation).
DREAMSCAPE. Dream manipulation.
ENEMY MINE. Human/alien interaction; space travel.
FIRESTARTER. Child with superpower.
FLY, THE. Science run amok; genetic tampering.
FREEJACK. Time travel; future dystopia.
GATTACA. Near future semi-dystopia.
GHOSTBUSTERS, PART II. Occult (ghosts, hauntings). (first one was better)
GREMLINS. Creature fantasy.
GROUNDHOG DAY. Self-enlightenment fantasy.
HIDEAWAY. Occult (near-death experience).
HITCHER, THE. Malevolent stalker with more-than-human attributes.
HONEY, I SHRUNK THE KIDS. Science run amok; gadgets.
ICEMAN. Caveman brought to life.
INTERVIEW WITH THE VAMPIRE. Occult (vampires—duh!).
JACOB'S LADDER. Occult.
JUMANJI. Fantasy; time travel; occult (haunting).
LABYRINTH. Fantasy (adolescent quest story).
LADYHAWKE. Fantasy (magic spells).
LITTLE MERMAID, THE. Fantasy (spells of transformation).
LITTLE SHOP OF HORRORS, THE. Human/alien interaction.
LOST BOYS, THE. Occult (vampires).
MAKING MR. RIGHT. Artificial intelligence.
MANNEQUIN. Fantasy (pygmalion).
MASK, THE. Occult (haunted object confers superpowers).
MULTIPLICITY. Cloning.
OUTBREAK. Biological disaster.
PEGGY SUE GOT MARRIED. Time travel.
PHANTOM, THE. Seeming super-powers.
POLTERGEIST II. Occult (hauntings, ghosts). (original was better)
POWDER. Mysterious powers.
REPO MAN. Human/alien interaction.
ROBOCOP. Future dystopia; gadgets.
ROCKETEER, THE. Fantasy; gadgets.
SIESTA. Occult.
STAR TREK III: THE SEARCH FOR SPOCK. Human/alien interaction; space travel; gadgets.
STAR TREK IV: THE VOYAGE HOME. Time travel; space travel.
STAR TREK VI: THE UNDISCOVERED COUNTRY. Human/alien interaction; space travel.
STAR TREK: GENERATIONS. Time travel; saving of universe.
STARGATE. Human/alien interaction.
STAY TUNED. Occult (human/devil interaction). 
SWITCH. Fantasy (gender switching).
TOTAL RECALL. Space colonization; mutation; psychological manipulation.
TOY STORY. Fantasy (toys come to life).
VICE VERSA. Fantasy (child/adult switching).
WAVELENGTH. Human/alien interaction.
WILLOW. Fantasy (witches, fairies, spells, etc.)
WITCHES. Occult (witches—duh!).