I don't usually watch science fiction movies, and rarely enjoy them when I actually do.  They usually seem fairly pedestrian when compared to either written SF or other movies.  I've made a few exceptions in the past couple of weeks, with, I'd say, largely positive results. But that's because the movies are odd.

First up, the Spanish time-travel tale Timecrimes. A middle-class householder in a new house sits in his backyard, looking around through binoculars, and sees an attractive young woman remove her shirt.  A little later, he looks again, and she lies unconscious and naked. His wife is off running errands, so he naturally wanders off to check things out. He gets pursued through the woods and ends up at a mysterious facility his realtor really should have told him about. Things go downhill from there.

Any low-budget loop-back time travel movie must be compared to the nerdy extra-credit-homework-assignment Primer. Timecrimes adds bare breasts and eliminates motivation, but leaves in the nerd (in the person of the stiff "Is this what it's really like in front of the camera?" director, Nacho Vigalondo). Primer was unsatisfactory in its human dimension, suddenly adding some murder-at-a-party huggermugger when it exhausts its initial  backwards-self-storage premise. Timecrimes starts out being about violence and sexual perversity, but never makes the existence of time travel make any sense at all.  Both are short, and kind of fun, and despite their flaws, are worth seeing. Neither is about using time travel to restore some lost love, which is a much more common, and more boring theme, using SF as just another way to deny the existence of death.

Intricate loopback time plots have been around for decades. I don't know if Heinlein's "By His Boostraps" was the first, but it was the one that caught my attention when I read it as a boy. That one relies on a startlingly obtuse POV character, but who wouldn't be obtuse when confronted with a double from the future?

The problem with each of these knots of crisscrossing character is that it exists without ever being tied.  It's as if they were created along with all of space-time.  All we see is the smooth embroidery on one side. What does the tangle of stitches look like on the back side? That's what I'd like to see.

The nerd in Timecrimes is a befuddled tech working the weekend in a gleaming but empty facility that apparently lets him monkey with the fabric of reality as long as he gets his regular job done. He is utterly clueless, and never seems to catch up with things, though you would expect him to have a bit of a jump on the main character, since he's been working with this machine for a while, and must have considered the possibilities. Primer really treats its nerd heroes with realistic respect. They aren't ethically superior to anyone, as the plot of that movie makes clear to them. But they can figure things out.

Timecrimes' soullessness is exemplified by the way it treats the main female character who, significantly, never even gets a name.  She is listed in the credits as La Chica en el Bosque, like some character in the background of a single scene.  You get to see her take her shirt off. You get to see her naked and unconscious. You get to see our former voyeur smack her around, chase her, force her to play the role of someone else, and then do something truly terrible to her. The movie would have left me feeling vaguely degraded if it had left me feeling anything at all. Because, of course, if someone has traveled in time, he knows things you cannot possibly know, and can take advantage of you in ways you cannot figure out.

The movie lets the main character be creepy, but why he's creepy, and what he's after, is completely obscure.

By their nature, time travel narratives challenge our understanding of free will. Now, of course, daily existence challenges our understanding of free will, if we're paying attention, but science fiction is about "heightening the contradictions", to use an old Marxist term.  Science fiction is the laboratory of exquisite tortures, and that is why we (or at least some of us) keep going back to it, to experiment with human needs, potentialities, and flaws.

Timecrimes does play the sexual perversity card, which, now that it is played, seems inevitable. As I mentioned, time looping gives you power, by giving you knowledge no one else has, or could have.
But that doesn't make the time looper smarter than everyone else. It only appears to. So the first thing I would do would be to have a really smart non-looping character. An outsider could actually spot the looping before the inside looper would, because he could see multiple versions of the same person. This would be an interesting conflict. And the looping character can excuse all sorts of vile behavior under the rubric of keeping paradoxes from consuming all of spacetime and bringing the universe to an end. Who can argue? I'm already thinking about the possibilities.

The existence of the time knot implies someone who tied it--and that entity is outside the immediate structure of the knot. A time machine exists--and does not stop existing, at least not in this narrative. In whose interest is this particular knot? What does it accomplish? It is not an accident.

Now Timecrimes gets along fine without that metanarrative, because it is a fast-paced violent movie that lets you see some skin. In this regard it is my favorite type of movie, fun, interesting, but with something missing, or a narrative path not taken. It gets the wheels turning.