The time-traveling “The Tomorrow War,” set largely in an alien apocalypse future, is a kind of throwback. Summer sci-fi spectacles like this – a sprawling, slightly sloppy, sometimes serious, often knowingly ridiculous extravaganza – aren’t quite the regular commodity they once were. “The Tomorrow War” isn’t as silly as Will Smith’s “Independence Day,” but, just the same, it’s Chris Pratt’s chance to punch some aliens. Pratt, star and executive producer of “The Tomorrow War,” used his box-office muscle to push forward the film, directed by Chris McKay and scripted by Zach Dean. Originally intended for theaters, McKay’s film got sucked into a future shock of its own during the pandemic and was sold to Amazon. It debuts on Prime Video this Friday. “The Tomorrow War” is by no means the first popcorn movie to go straight to the home, but it’s still one of the popcorn-iest. For those looking for that kind of summer-movie escape, “The Tomorrow War” should fit the bill. It’s tonally scattered and massively implausible. But in movies with aliens, time loops and machine guns, those are more features than bugs. Pratt stars as Dan Forester, a military veteran turned high-school science teacher. He and his wife, Emmy (Betty Gilpin) have a young daughter named Muri (Ryan Kiera Armstrong). The world, though, gets a rude interruption when, in the middle of a televised soccer game (presumably because “The Dark Knight Rises” already did cataclysm in a football stadium), a portal opens on the field and out walks futurist soldiers with a message: In 30 years, an alien invasion will consume the world. To defeat the “white spikes,” as the voracious invaders are called, they need help from past. They need to send fresh recruits to the battle through a time link that only goes back and forth from the present to three decades ahead. Plenty of international rancor and television-news debate follows. This is their war, not ours, some claim. In the foretold, near-future apocalypse there are clear echoes with today’s existential distress over climate change. It’s a backdrop for countless – maybe all – disaster movies of the last few decades. But “The Tomorrow War” cleverly couches its planetary metaphor in sci-fi action that culminates, ultimately, in the icy north. Forester is drafted, implanted with a digital arm band that allows him through the portal. So desperate is the fight that the recruits are both trained military and wide-eyed civilians. His going off to war is portrayed with heartfelt emotion and a sincere sense of sacrifice. In Forester’s father (J.K. Simmons), a Vietnam veteran who couldn’t readjust to family life after, the toll of soldiering is connected through generations. In the “tomorrow war,” only 30% return, Emmy says, and most that do are a shell of themselves. “The Tomorrow War” spends most of its time in the future, but its central theme is timeless: the replayed tragedy that sometimes you don’t come home the same from war. The mix of civilians seems also intended to bring in some funnier folks to the fight. That includes Mary Lynn Rajskub but especially Sam Richardson, who immediately befriends Forester with his nonstop, anxiety-induced, deadpan prattle. Richardson, a veteran of “Veep,” is really good at this, and it’s cheering to see him more center stage. (He’s even better in another new release that blends horror and comedy, “Werewolves Within.”) McKay, director of “The Lego Movie,” is most at home in humor, and “The Tomorrow War” can be funny. It’s less adept at some of the operatic notes it tries to strike, but, well, aliens can be tricky. “The Tomorrow War,” an Amazon Studios release, is rated PG-13 by the Motion Picture Association of America for intense sequences of sci-fi violence and action, language and some suggestive references. Running time: 140 minutes. Two and a half stars out of four.