Ezra Miller delivers a massive jolt as The Flash

Time travel. Multiverses. Babies falling out the window of a collapsing Gotham City hospital in a hilariously horrifying slo-mo sequence.

It’s a busy day for Barry Allen, who, when he’s not zipping around faster than a speeding bullet as The Flash, really just wants his regular café order. You can’t blame the guy; the calories he must burn.

And burn them he does in “The Flash,” a worthwhile entry in the DC Extended Universe that also, ironically enough for a movie about changing fate, serves as a soft reboot of the DCEU as it becomes the DC Universe under the helm of James Gunn (director, “Guardians of the Galaxy”) and Peter Safran (producer, “Shazam! Fury of the Gods”).

Directed by Andy Muschietti (who was just announced as the director for DCU’s “Batman: The Brave and the Bold”) from a screenplay by Christina Hodson, “The Flash” furthers the backstory of Barry Allen/The Flash (played once again by Ezra Miller; more on that later), who we met in earlier DCEU films, particularly “Justice League.” (Watch the Zack Snyder cut; you’ll be better off for it.)

If you’ve seen any of the trailers, you’ll know “The Flash” has Barry traveling through time to prevent the murder of his mother (Maribel Verdú) and wrongful imprisonment of his father (Ron Livingston) — and, wouldn’t you know, things don’t go as planned. (The movie is based on the DC comic book storyline “Flashpoint.”)

What results is a phenomenal use of one actor playing two roles: Miller portrays not just the current Barry — the desperately lonely, endearingly awkward young man who just can’t seem to catch a break (and no, gaining superpowers after being struck by lightning doesn’t count) — but also a younger Barry, one whose worldview is radically different, unaffected by trauma and loss and Justice League members not doing their parts.

Miller’s off-screen drama is well-documented: In the past few years, they’ve been accused of multiple crimes, including assault, burglary and more. When it comes to being Barry/The Flash, though, it’s all engaging professionalism. Time and again, Miller brings charm and humor to both roles, helping to anchor the film’s otherwise chaotic 144 minutes. (You’d think a film in which the superheroes move so far they slow down everything on the screen wouldn’t be so frenetic, but here we are.)

We don’t just get one Flash, either. Two timelines colliding means we also get two Bruce Waynes/Batmans. The first one is the more recent one: Ben Affleck, looking just as lonely as the older Barry and doling out sage advice about the Butterfly Effect and how loss shapes them both. The second? Michael Keaton. Yes, he of 1989 “Batman” fame. And he brings all the fun and retro tech you could
ask for.

But it wouldn’t be a superhero movie without a big bad. Unlike the welcome inclusion of a previous Batman, though, the villain here is an uninspired General Zod (Michael Shannon), the antagonist of “Man of Steel.” (Honestly, anything that isn’t Barry talking to Barry plays second fiddle.) But instead of Superman joining the fight this time, we’re introduced to his Kryptonian cousin: Kara Zor-El/Supergirl (Sasha Calle).

Don’t expect the same type of action you’ve seen in other DCEU movies. The Flash (Flashes?) is fast (so fast he can rewind time), but the action sequences here are generally about position, strategy, advantage. It’s a treat to see the Barrys race around causing lightning-infused chaos, even if the visuals are a bit lackluster at times.

In the end, “The Flash” does what it set out to do: to help soft reboot the DCEU continuity into the DCU with a generally enjoyable, if slightly too long, superhero film. (“Aquaman and the Lost Kingdom,” scheduled for a December release, is meant to be the final film in the DCEU.) Miller delivers charm and humor twice over, and gets a Bat Signal-size helping hand from Keaton, who’s clearly enjoying himself here. It gets a little muddled at times, and let’s not talk about the inconsistent calorie-intake situation, but the DCEU could have done a lot worse than closing out its final act with a pair of speedsters and some hardened vigilantes trying to save the world.

Three “You didn’t tell me we could get shot!” stars out of five.