PHOTO COURTESY WARNER BROS. / DC COMICS

Well, it didn’t go well for Loki or several distinct Spider-Men, but perhaps The Flash will figure out a way to alter time without ruining everything. (To be fair, those other guys work for the studio across town, so The Flash might not be aware.)

In “The Flash,” somehow just the first solo big-screen adventure for the iconic superhero, Barry Allen (the embattled Ezra Miller) is mired in a childhood tragedy. His mother (Maribel Verdú) was murdered years ago in a random act of violence; his father (Ron Livingston) was wrongfully accused of the crime and is about to lose his last appeal.

In a fit of misery, Allen … well, runs really far, really fast. Those are his powers, after all. This time, however, he runs so far and so fast that he briefly travels back in time, due to some timey-wimey stuff about the speed of light. Despite a stern warning from Bruce Wayne (Ben Affleck), he attempts to go back far enough to save his mother.

Unfortunately, things go astray, and the Flash ends up in another reality, where his mother is alive — but there are a lot of key differences. For one, there’s another version of himself (without the superpowers) hanging around. Oh, and Superman doesn’t exist — which is a bit of a problem, because General Zod (Michael Shannon) just showed up to conquer the planet. To solve that one, the two Flashes will have to beg for help from the only superhero they can find: Batman.

Not the one from earlier in the film, however. This is an older and surlier Dark Knight, played by former Bat actor Michael Keaton.

There’s plenty of half-explained twists and surprising cameos in “The Flash,” keeping things moving at a pretty good clip despite a slightly stretched runtime. When the movie is fun, it’s very fun; the action sequences are compelling, the winks and nods are delightful and there are enough superhero team-up moments here to rival anything in the bloated “Justice League” film.

Like many films in the soon-to-be-reset DC Extended Universe, it has slow stretches; “The Flash” never earns the gravitas it occasionally deploys. But the good stuff is more than enough to keep you hanging around through the slogs.

Most vitally — and accuse me of hometown bias if you must — Keaton is a delight. Seeing the most iconic Batman back in his suit is an unabashed thrill, and director Andy Muschietti is smart to surround him in the trappings of the Tim Burton films (including long stretches of Danny Elfman’s perfect theme music). It may say “The Flash” on the poster, but our favorite Batman steals the show.

My Rating: 7/10

“The Flash” is now playing in theaters.