Even though it creates a lot of original possibilities, time travel can be a tricky thing to put into sci-fi movies, and it can ruin endings if not done well. Handled properly, it can be used to create fascinating loops that make fans ruminate over the different timelines presented. However, if it’s used to hastily shoehorn an ending at the last minute, it can ruin everything that worked in the narrative leading up to it. Often, time travel appears as a deus-ex-machina moment to wrap up a storyline that the writers don’t know how to end in a way that makes sense.
For time travel to work well, especially if it’s the biggest element that a sci-fi movie hinges on, it needs to be incorporated in a way that doesn’t challenge its own rules. The logic established in the world-building has to remain consistent, or the time travel element will just seem hokey. These sci-fi movies either used flimsy science to explain their time travel, leading to anticlimactic endings or tried to wrap everything up by eradicating every last flaw with a handy time travel solution.
8 Lost in Space (1998)
The original Lost in Space The series from the ’60s had a heartwarming futurism charm that the late ’90s film tries to recapture while adding more action. It mostly succeeds, particularly with its solid cast led by William Hurt as a family of interstellar explorers searching for an habitable Earth-like planet. Whereas the series got lost in space, this movie gets lost in time, with an ending that implies the only way to resolve the issue of the family crashing into a hostile world and learning to value its bonds in dangerous situations is with a deus-ex -machine moment that returns them right back to the moment the ship takes off.
7 Timeline (2003)
In an interesting mishmash of genres, Michael Crichton’s timeline finds a professor stumbling into a wormhole at an archeological dig and flung back to 14th-century France. A scientist peer organizes a rescue team using a teleportation device, including the professor’s son and his protégé, who are forced to find allies during one of the bloodiest battles between France and England. The scientist has no intention of letting them come back, given the very flimsy motivation that he’s certain they’ll expose his wormhole if they do, and promptly tries to sabotage the transportation device, only to be cast into medieval times himself.
6 The Fountain (2006)
A medical researcher tries, unsuccessfully, to cure his ailing wife’s tumor, wasting precious time with his nose in a book as she’s wasting away. Eventually, after she passes, he undertakes a transcendent journey to find her, which spans the concepts of space and time, as they are reunited and then ripped apart through the ages. In the final moment, he drinks sap from the Tree of Life in a loose reenactment of an earlier Mayan creation myth and his body turns into flowers as a final acceptance of death. While the visuals are striking throughout the movie, this final cyclical moment in the ending removes humanity by going completely cerebral.
5 Deja Vu (2006)
Denzel Washington turned down a role in Terminator 2 but did eventually make a time travel movie as an ATF agent using it to prevent a ferry from exploding in New Orleans and killing over 400 people. A surveillance system called “Snow White,” which uses satellite footage to create a time window of events days before they occur, allows Washington’s character to sacrifice himself to stop the bomb from ever exploding. This would have been heartbreaking for his love interest if he didn’t just pop back up from another timeline and get the girl in the end like nothing ever happened, while also creating a time travel paradox.
4 The Jacket (2005)
When an amnesiac veteran of the Gulf War finds himself inexplicably standing at the scene of a murder, he’s taken to a mental institution and subjected to several strange experiments involving a straight jacket. Confined on his own, he learns that he can time travel to the future, where he tries to work backward and piece together clues of his condition. This movie suffers from a lot of time travel whiplash, which not only becomes confusing but results in an ending that feels very anticlimactic considering all the lead-up to how it ended up at the murder scene in the first place.
3 Clockstoppers (2002)
Produced by Nickelodeon Movies, Clockstoppers opens with an exploration of Hypertime, a futuristic technology intended to speed up one’s molecules to such an extent that the world looks like it’s standing still. The CEO of the company developing the technology decides to use it for world domination, but his plans are foiled when a Hypertime watch finds its way out of the lab and into the hands of teenagers. As goons get sent to retrieve the prototype hijinks ensue, but thanks to the Hypertime watch, nothing done in the movie ever sticks or seems to have any consequences, and the teens even get to keep it at the end.
2 Trancers (1985)
Copying the success of Terminator, Trancers follows a bounty hunter named Jack Deth who travels back to Los Angeles from the 23rd century, intent on bringing an old enemy to justice. He’s able to travel back in time by injecting himself with a drug that lets him possess the body of an ancestor, and when he eventually locates his nemesis (also an ancestor’s body), he has to make a choice; either send him back to their century to be punished, or send himself back, but someone is getting trapped in 1985. Eventually, the time travel methodology breaks down and creates the one problem sci-fi time travel movies never resolve.
1 Freejack (1992)
Rather than be able to invent synthetic organs to bolster their health, elderly clients in Freejack’s 21st century send thieves back in time to kidnap healthy young people to have their brains put into their bodies. When a young race car driver is taken but ultimately escapes his captors, he becomes a hunted fugitive on the mean streets of the future. It tries to pull from blade runner and Terminator to be a cyberpunk or neo-noir movie like other more successful movies from the ’80s but ultimately comes across as a poor imitation.