io9
Some of the greatest battles in science fiction haven't involved dogfights or shoot-outs, but time-traveling smackdowns, with two different people trying to change history out from under each other. Like Marty and Biff, trying to wipe out each other's timelines in this clip from Back To The Future 2. As soon as you have more than one time machine, you can have timeline-altering sniper fights, and whoever can erase the other person's time line first wins. Start your paradox engines, and may the slipperiest time-trickster win!
Some of the greatest battles in science fiction haven't involved dogfights or shoot-outs, but time-traveling smackdowns, with two different people trying to change history out from under each other. Like Marty and Biff, trying to wipe out each other's timelines in this clip from Back To The Future 2. As soon as you have more than one time machine, you can have timeline-altering sniper fights, and whoever can erase the other person's time line first wins. Start your paradox engines, and may the slipperiest time-trickster win!
Time Cop. Jean-Claude Van Damme is the only one who can safeguard history against those who would change it for their own evil ends. But a corrupt U.S. Senator (Ron Silver) is messing with the timeline in order to become president in 2004. Van Damme quickly figures out what's going on. But then Silver changes history some more, so when Van Damme returns to his present, everything has changed and Van Damme no longer has a job. It's up to Jean-Claude to go back once again and change the past a second time, getting rid of Silver in the process. Weirdly, this is one of the best movies about time travel in spite of its action-movie star.
(Versions of Van Damme's Time Cops show up a lot in SF, including the ChronoGuard in Jasper FForde's Thursday Next novels, and the temporal police from the 29th century, who show up in Star Trek: Voyager a few times. Stephen Hawking has famously theorized that some kind of temporal police must exist, to prevent the horrendous paradoxes that would otherwise happen. In Ken MacLeod's Newton's Wake, they're referred to as the "Quantum Angels.")
Primer. Abe and Aaron create a time machine, which requires you to lay inside it for as long as you want to go back for. They go back and start meddling with their own pasts, speculating on the stock market and tinkering with other things. But soon they're making more serious changes — knocking out their past selves and taking their places. They live through the same day or two over and over again, creating alternate timelines with subtle differences each time. Eventually, Abe and Aaron start trying to counter each other's interference, but keeping up with which version of Abe or Aaron you're seeing gets trickier and trickier.
Back to the Future Part 2. When "Doc" Brown carelessly leaves his Delorean time machine unguarded, that big lunkhead Biff goes back in time to 1955 and gives his younger self the means to become rich and powerful far beyond his pathetic dreams. Our hero, Marty, has to go back in time to 1955 for the second time in a row — except instead of changing Biff's future as he did in the first movie, he's just trying to undo the changes that Biff has already made. 
Up the Line by Robert Silverberg. Jud Eliott III gets a job as a time courier, showing tourists the wonders of history. But some of his crazy colleagues start messing around with the timeline and wrecking history, so he has to keep going back and trying to fix the damage without attracting the attention of the Time Patrol. And then he falls in love with a time paradox named Pulcheria, his own great-great-great-great-grandmother, and it all goes to pot.
The End Of Eternity by Isaac Asimov. Harlan belongs to a time agency called Eternity, which exists outside of time itself. He and his fellow agents go around changing history to reduce human suffering. But then Harlan has a falling-out with his bosses over his girlfriend Noÿs, whom they want to erase from history. Harlan is supposed to help one of his colleagues, Cooper, go back to the 24th century and become the scientist whose discoveries later make the Eternals possible. In a fit of pique, Harlan sends Cooper back to 1932 instead, so he can't lay the groundwork for Eternity and Eternity will never exist. Finally, after the Eternals un-erase his girlfriend, he agrees to go back and rescue Cooper from the past — but then his girlfriend Noÿs reveals that Eternity's secret purpose is to edit history to make sure humans never colonize the stars. So instead Harlan helps her to change history so that humans discover atomic energy earlier, and start down the path of space exploration. As a consequence, Eternity ceases ever to have existed.
Lightning by Dean Koontz. Laura has a guardian angel who shows up to help her whenever she's in danger, but then it turns out other people are trying to undo the "angel's" work. Some evil Nazi time travelers are trying to destroy Laura. As Laura's son explains:
They can hopscotch around us.. They can pop ahead in time to see where we show up, then they pick and choose the easiest place along the time stream to ambush us. It's sorta like... if we were the cowboys and the Indians were all psychic.It also contains the great line, "How can you win against goddamn time travelers?" How indeed?
Doctor Who. For a show all about time travel, Doctor Who doesn't have that many stories where the Doctor and another time-traveler are both changing the timeline back and forth, surprisingly. But the Doctor and his fellow Time Lord the Master get into some duels on a few occasions. The most over-the-top is in the comedy special "Doctor Who And The Curse Of The Fatal Death," where the Master and Doctor meet up in a castle. The Master goes back in time and bribes the architect to put a trapdoor right where the Doctor happens to be standing. But then it turns out the Doctor also went back in time, and bribed the architect even more — to put the trapdoor where the Master is standing instead.
Dirk Gently's Holistic Detective Agency by Douglas Adams contains a lot of cris-crossing back and forth in Reg Chronotis' time machine (much of which is lifted somewhat from the episodes Adams wrote for Doctor Who. In particular, the ghost of the last surviving Salaxian possesses a disgruntled literary magazine editor, inspiring him to go back in time to repair the Salaxian spaceship before it can explode, back at the dawn of life on Earth — which will have the effect of making sure life never develops on this planet. The instructions for fixing the ship are buried in the second half of Coleridge's poem "Kubla Khan." But Chronotis and Dirk Gently, our detective hero, go back to Coleridge's time and ensure he never finishes that poem, so the instructions are lost and the alien plot is foiled.
Terminator. The Terminator movies and TV show are all about people and cyborgs traveling back in time to change, or safeguard history. The machines want to kill Sarah Connor before she can ever give birth to future resistance leader John Connor, so John sends Kyle Reese back in time to protect him — and Kyle becomes John's daddy. And then, the machines send more cyborgs back to kill John, and eventually Kyle's brother Derek ends up back in our time hanging out with his friend/nephew as well. And Sarah Connor either dies of cancer or travels forward in time past her own death date and somehow avoids it. Maybe in the second season of Sarah Connor Chronicles the machines will figure out they just have to wipe out the Reese brothers as kids, and all their problems go away.
Time After Time. H.G. Wells and Jack The Ripper battle each other in the bizarre future of 1979. Once they both reach the future, time travel doesn't play that much of a part in the story — except that at one point, Wells travels forward in time three days with his girlfriend Amy, only to find Amy's obituary in a newspaper. They have to travel back again and prevent Jack the Ripper from making Amy his fifth victim. (In the end, it turns out the obituary was mistaken, and it was Amy's friend who was murdered.) And then Amy goes back to the 19th century and marries Wells, changing history at least somewhat. 
Meet The Robinsons. An animated Disney film, very loosely based on the book A Day With Wilbur Robinson. Tom Selleck invents a time machine. (We'll just pause to let you absorb that piece of info.) And then a villain named Bowler Hat Guy travels back in time to sabotage a memory-scanning machine that a kid named Lewis has invented, which gave rise to all the amazing inventions in Tom Selleck's utopian future. ("Tom Selleck's Utopian Future" will be my next band name.) So Tom Selleck's son Wilbur has to travel back in time to our time, to make sure Lewis repairs the memory-scanning machine.
Crime Traveler. In this British TV series, a physicist named Holly Turner invents a time machine, and a lazy detective named Slade uses it to travel back in time and solve crimes before they happen. But in the final episode, a criminal gets his own time machine, and travels back in time to give himself an airtight alibi for a couple of murders. Slade has to travel back as well, to catch the other time traveler in the act.
Research by Nivair Gabriel
Comments
A great example of this is the current Booster Gold series from DC Comics. Two rival teams of time travelers, each with their own Time Spheres, and at the same time you get some fun stopping by the best moments of DC history.
@Gaambit: Oh yeah, good one... I was just reading a couple issues of that the other day. It's pretty great stuff.
What about the recursive temporal battle between the Steel General and Set in Roger Zelazny's magnificent Creatures of Light and Darkness?
That single encounter outstrips anything described above in terms of audacity, adrenaline, and imagination.
A runner-up would be the fast-time encounter between the Shrike and Rhadamanth Nemes in Dan Simmons' Endymion.
What about the time travel genocide that the Doctor did? The Timelords and the Daleks both were killed off.
Bill and Ted
"Dude, we just have to remember to hide the key to the cell under this bucket."
"Righteous!"
[Unlocks cell with key]
In the Terminator franchise, why don't the future machines just go back and kill Sarah Connor's parents? Or their parents?
All You Zombies by RAH- as I recall not a duel, but worth mentioning in the context of time travel. The Big Time by Friz Leiber is a good example of the Time War genre. And of course the old Time Patrol stories by Poul Anderson and Andre Norton's Time Traders books. Murray Leinster's Time Tunnel was the basis of the TV show, I think.
Wow, I totally forgot about the movie Primer. I'm definitely going to have to see that movie again because I vaguely remember enjoying it.
Love Primer.
I feel these are always a good chance to spout off similar films soooo, my picks.
Millennium, Kris Kristofferson at his best.
And Time Rider.. A true lost classic.
Dude--Bill and Ted's Bogus Journey? Anyone?
"But when I win, I'll just go back in time and give myself another gun!"
Mr. Fantastic/Dr. Doom have had some great time duels over the course of the comic. There was a great issue toward the end of Walt Simonson's run (325 or so) where the issue runs backwards as Reed and Vic keep trying to leapfrog each other back to get the first shot in.
You forgot how skynet sending the terminators back in time created itself and john connor, the archetech of its own undoing. I really loved when I realised that as a kid, blew my mind.
I think that a Star Trek based tv show on the temporaral police would be awesome.
There was also that red dwarf episode where Rimmer and Lister discover that the photo developing chemicals have mysteriously changed over the 3 million years. And they keep going back in time to try and give their past selves a stupid idea that will make them rich and won't leave them stranded on red dwarf.
@learned_hands: Whoops, it was issue 352. Quote from Simonson: I did a Doctor Doom/Reed Richards time fight in FF #352 where the reader has to read the comic twice, once in sequence by page number, and once in a sequence jumping backwards and forwards through the comic...The reader has to flip back and forth through the comic, because Doom and Reed were jumping around fighting through time, and I laid the book out in a way that made the reader jump around through the comic in order to follow their fight. Essentially, the page layout created a physical metaphor for their time duel.
@joemono I remember something about how nobody knew much about John Connor's origins other than his mom was named Sarah Connor and that she was in L.A. in the early 80's.
@joemono: I think that since Judgement Day changes with each movie when things are changed that if they did go back, that would result in a different Judgement Day, which would mean that the one who sent back the T to kill them would never have existed. OK, skull hurts.
@Hauler: Me too, I'm totally going to have to go re-watch this one.
The main thing I never understand in time travel movies is how the characters can remember the other timeline once it's been changed. If the past was changed that character shouldn't remember the alternate version of events, right?
The fact that the "Bill and Ted" movies aren't on this list is a travesty. Aside from the aforementioned "Excellent Adventure" escapades, "Bogus Journey" contains the righteous battle with DeNomolos, who sends evil robot versions of the best buds to kill and replace them. The finale with the "time game" face off is the best use of time travel fighting i've ever seen.
@Gaambit: Don't you mean Green Lantern? j/k
Another impressive list, Charlie. Brought back some memories... sadly, I cannot go back in time and relive them. Screwing up the timeline is like crossing the streams: BAD.
Wow this is my most fave genre. The rest of you can enjoy your recycling same old star wars/star trek, but the time travel and parallel worlds genres are so cool.
I just hope they stay cultish. There's not been a TV series that really grabs the time travel genre and goes with it yet.
Crime Traveller looks wicked, I'm going to download that right now!
@burlives: Okay, so send a skinjob back to get to know her. They can time travel, but they can't figure out anything about someone's past?
@Blitzgal: Probably belaboring something obvious to you, but there are 2 versions of that situation. In one, the traveler started in a different timeline, went back and lived into a different future, retaining memory of the old timeline. In the other the characters in the new future who haven't time-traveled shouldn't remember the old timeline but in cheesy movies often do.
You forgot that shitty movie Paycheck with Ben Affleck.. I remember being more interested in the time machine than the plot itself..
Seriously? Timecop but no Heinlein? io9, I'm not sure I love you anymore.
thank you for including Primer, i consider that the greatest time travel movie of all time. I wish he would make another movie. Thanks for the primer reference.
@burlives: Actually, the original Terminator did kill Sarah Connor's mother. That's how he tracked them to the Motel.
@syncpulse:
And there's the Red Dwarf episode where they accidentally prevent Oswald from shooting Kennedy. Then they have to kidnap Kennedy and convince him to shoot himself for the good of the future!
Oh...and the episode where Lister leaves himself as a baby under the pool table. Lots of good time travel stuff in RD.
Didn't the X-Files have a time traveller who killed his own team and himself to prevent time travel from being invented?
I always really liked the Quantum Leap episodes toward the end with the evil Leaper.
Lightning was an amazing book... How is it that it hasn't been mangled into a movie yet?
@Mathmos: Shouldn't even the time traveller lose his memory of the alternate reality as soon as history is changed? Once the timeline was changed then he never experienced the first version and should only have a memory of the new version.
I also enjoyed the Red Dwarf where Kennedy kills himself to maintain a hero image rather than the loser he was to become had he lived.
Another thumbs up for Primer. And Millennium, while not a time-travel-duel story, was great too. Cheryl Ladd had the biggest hair I've ever seen.
I feel that "Bender's Big Score" ought to be mentioned here.
Gawd I hate time travel stories. They are almost never done well (i.e., paradoxes are either ignored or abused to the point of nonsense). It is almost always guaranteed that a good show/movie can be ruined (for me) by the writers adding time travel to it.
Of course, it should be noted that The Curse of Fatal Death was written by none other than the multi-award-winning Stephen Moffat, who, I don't think it's unfair to say, is the best writer out of the cadre of writers on the new series of Doctor Who.
[en.wikipedia.org]
Primer is made of awesome.
The only scene I remember from time cop:
+ Watch video
Hooray for Douglas Adams!! Also, no Quantum Leap io9?? WTF...
Time after Time is a sentimental favorite of mine. I can't be the only one who was creeped out by that as a kid, can I?
Harry Harrison, The Stainless Steel Rat Saves The World. A classic and is all about time war. How could you miss out ole slippery Jim diGriz?
Or, Futurama: Bender's Big Score.
That had some pretty awesome time-travel-dueling in it.
That was really just a great movie, actually. In fact, Futurama was a great TV show.
IN FACT, what the hell am I doing here? I'm going to go watch Futurama.
@Blitzgal: Maybe not. It might be all confusing like quantum mechanics, i.e. the two realities exist at the same time, but the time traveler only observes the one that he 'made'. Plus, if he didn't remember the original one, then that would in itself create a paradox, because then he would have no reason (and possibly no means) to go back in time.
No "Time Stalker" with William Devane and Lauren Hutton? C'mon, it was possibly the worst TV-Movie ever. Devane is a history professor who notices in a picture taken in the old west that the outlaw is carrying a modern Colt Python .357 Magnum?
@joemono: They don't know who John's mother is to get to know her. All they know is that she's named Sarah Connor and lived in LA -- in the first movie, the Terminator killed two women before finding the right target.
I've been fond of a little-known, out-of-print book by Keith Laumer called "Dinosaur Beach." It's all about time travel duels, between various time traveling societies, and constantly loops back to the aforementioned beach. By now, it's as quaintly dated as Asimov's Foundation, and it could use a few breaks from the action, but outside of "Time Traveler's Wife," I can't think of anything filled with the time traveling equivalent of pornography.
A link to a free copy is here:
[www.webscription.net]