Because it begins with Julio (Julián Villagrán) waking up confused and disoriented in the bed of Julia (Michelle Jenner) after a one-night stand neither much remember, and ends with a sensitive and heartfelt declaration of one's love for the other, Nacho Vigalondo's Extraterrestrial is more than anything else a traditional romantic comedy. Its basic narrative turns are guided by largely generic principles, all expertly applied: the young couple strain comically to deflect the suspicions of Julia's unwelcome current boyfriend, Carlos (Raul Cimas); a hapless nosy neighbor seething with jealousy wises up to the cuckolding and plans to foil the affair; and furtive hand-holding leads to discreet make-out sessions and eventually secret quickies whenever Carlos isn't looking, which is amusingly often. And many of the film's simplest pleasures are entirely typical of an exemplary rom-com: Its lead lovers are charming and magnetic together, their dialogue is marked by wit and charm, and the romance which blossoms between them feels completely believable and true. In almost every respect, Extraterrestrial is an exceptional romantic comedy. It just happens to be set during an alien invasion.
If there's a clear precedent for this kind of self-conscious genre-hijacking, it's probably Edgar Wright's breakup-comedy-slash-zombie-apocalypse hybrid Shaun of the Dead, though it wouldn't be accurate to call Extraterrestrial parodic. Wright took a close, loving look at the zombie movie and lifted its traditional generic framework wholesale, replacing only the clichéd Hollywood details with the minutiae of working-class, slacker-style Britain, and the result was fun but, because of the single-mindedness of its method, almost necessarily formulaic. Vigalondo's approach feels much less by-the-numbers, which lends the proceedings an air of spontaneity Wright's rigor couldn't have made room for. And so while on paper Extraterrestrial might strike the skeptical as conceptually gimmicky or overly self-aware, in practice it's hard to say precisely what Vigalondo is doing and even harder to guess how it will all play out. Even overtly bizarre films struggle to remain novel and unpredictable throughout their running times; for a film that's essentially a genre picture to do it effortlessly is all but unheard of.
Consequently, much of the joy of watching Extraterrestrial comes from the surprises its narrative offers, and I'd be remiss to spoil the particulars. But it should probably be noted that the film's science-fiction elements exist only on the periphery—or, to put it another way, the entire film seems to exist on the periphery of some other sci-fi blockbuster, where they manage to mostly stay out of one another's way—and the titular beings are elided altogether. We hear of "invasion," but of the 30-odd alien ships said to be floating above the country we only see about an eighth of a single one, glimpsed obscurely and from afar. Like his debut Timecrimes, Extraterrestrial deals with fantasy while remaining grounded in naturalism, delivering the special without the effects (the most menacing weapon in the film, of course, is a large jar of peaches). But it never feels like a case of thrifty obfuscation or needless misdirection; the de-emphasis of all things literally extraterrestrial emerges organically and with entirely good reason, which is to say that Vigalondo effectively writes around aliens he himself created. It's an audacious strategy.
Asking your audience to care more about whether cheating lovers will be caught than whether invading alien spacecrafts will end the world as we know it is a major gamble, and in less capable hands the film's very premise might have been a classic case of burying the alien lede. But Vigalondo is commendably dedicated to seeing his own conceit through, and by the end of the film we find ourselves invested enough in the human drama—as well as the surprising and often outrageous comedy which surrounds it—that the presumptive invasion itself comes to seem no more relevant to the film's appeal than the devil is to Heaven Can Wait's. Aliens may be the catalyst, but all of the tension, action, and drama that follows is strictly human—and remarkably resonant.