The National scaled majestic rock as the façade of City Hall became a psychedelic light grid. Goth-pop princess Lorde proclaimed her night magical, as was her set after a three-hour storm delay. And the Replacements hit town for the first time in 23 years, rocking both old and young fans silly with garage-punk nuggets.

The fourth edition of Boston Calling provided a glorious mixed bag across the past three days at City Hall Plaza, opening with a bang on Friday night and closing with its most stacked, diverse lineup yet on a perfect-weather Sunday. Saturday grew problematic with the event’s first-ever evacuation to wait out thunderstorms, a smart move for safety, though it left throngs in the streets and bars as well as under City Hall’s VIP alcoves for that extended wait. It didn’t help that Volcano Choir and Girl Talk never got to play after the Hold Steady had mustered some momentum with its Springsteen-tinged guitar rock behind frontman Craig Finn’s constant wide-armed gestures.

After social media helped beckon the faithful back to the plaza, however, Lorde emerged about 9 p.m. and set it all right. “I’m so, so grateful to you for staying,” the 17-year-old New Zealand star told the crowd. And backed by a drummer and keyboardist, she worked her narrow sonic palette with sincerity and grace, while losing herself into spastic dance contortions when the beats kicked in. When she ditched her black jumpsuit to emerge in flowing red cape and crown for “Royals,” it felt like a shared coronation, with fans singing along, “Let me live that fantasy!” Seconds after Lorde’s finish, Childish Gambino cranked up on the alternate stage as if to keep the crowd from leaving, though “Community” actor/rapper Donald Glover’s broad, busy and evolving hip-hop pastiche proved a confusing contrast.

Sunday pretty much delivered from top to bottom, though for split factions of fans. The kids went wild for English quartet the 1975 (despite or perhaps partly because of singer Matthew Healy’s detached flourishes to the atmospheric alt-rock) and especially for Twenty One Pilots. That Midwestern duo stormed the stage in Ninja-like masks to bash through sleek piano/drums pop, Eminem-ish raps and even a soft ukulele changeup of Elvis Presley’s “Can’t Help Falling in Love,” a mish-mash often more crowd-pleasing than musical. And young devotees sang along to it all, waving their hands high and even supporting a drum-kit platform that flamboyant Josh Dun broached the barricade to play.

Those two late-afternoon bands came between guitar-centric outfits favored by other, partly older fans. On the early side, Texas quartet White Denim shifted and stung like a prog-rock ZZ Top, jamming far beyond the blues with twin guitars and active rhythms. But the more textural glide of the War on Drugs, led by Bay State native Adam Granduciel, tended to wash into mid-afternoon background sound (in keeping with the title of the band’s fine new album Lost in a Dream), despite wondrous surges. And the Boston-bred Lake Street Dive was the day’s starkest standout with jazzy soul-pop that charmed friends and newbies alike as soon as singer Rachael Price opened her mouth. Price soared over the spry retro-groove (and whistling of guitarist/trumpeter Mike Olson) in “Bobby Tanqueray” and she testified like Etta James with crowd-cheered vocal inflections in “Don’t Make Me Hold Your Hand.” In one of two new songs, Price teased about breaking the good-girl mold, singing “Can’t you see this is only the beginning.” With this band, yes.

Edgier pop-rock returned after sundown with another Texas outfit, Spoon, which explored its dark and light duality, from its stage attire (three musicians in black, two in white) to songs that veered from cool to funky, seductive to dissonant. Yet singer Britt Daniel broke the black-and-white mold to sport a Red Sox cap for the “The Underdog,” probably not a coincidence given the home team’s recent turn. Daniel also had the nerve to salute the Replacements by suggesting they should have new songs, though the ’Mats charged through their return with proven fare.

The most notable first impression cast by the matured, half-original Replacements was how tight and forceful they sounded, perhaps too tight for a band that forged its legacy on sloppy (i.e. drunken) performances. The quartet (with local Neighborhoods veteran David Minehan on lead guitar), proved able to stop on a dime in songs including “Can’t Hardly Wait” and even the early thrasher “Love You Till Friday,” which morphed into Chuck Berry’s “Maybelline.” But the ’Mats luciky began to show their seams, when Paul Westerberg went from joking about not knowing what to play to actually forgetting lyrics in “Androgynous” and seeking help from his old bass foil Tommy Stinson at the same mic. Westerberg also blew a mean harmonica in “White and Lazy,” and it was a great sight to see teenagers and geezers alike shouting along to “Bastards of Young” on the railing in front of the stage.

In another sharp contrast of style for the audience, Sunday’s final set again cut to hip-hop with Nas and the Roots, together and separately. Alas, except for a couple of quick jams, that turned out to be separately for the most part. Veteran MC Nas has been showcasing his 1994 classic Illmatic, but he mixed it in a half-hour opening that hit a peak with the fierce bravado of “One Mic,” before the Roots crew took over the second half, working their own catalog as well as such divergent covers as Kool & the Gang’s “Jungle Boogie,” Guns N’ Roses’ “Sweet Child O’ Mine,” and George Thorogood’s “Bad to the Bone.”

There’s a different vibe to Boston Calling at night, when the screens are going, the light show’s darting around the face of City Hall and the bands sound better in the still air. And perhaps that works best on opening night when everything’s fresh, before the diverse, daylong marathons. It certainly worked Friday, when Neutral Milk Hotel brought much of its 1998 cult landmark In the Aeroplane Over the Sea to life, from the folky solo tunes of reclusive singer Jeff Mangum (hard to see in his cap and wooly beard apart from his ban on cameras and video screens) to the ensemble’s lovely, shambolic din of horns, accordions and singing saw. You could imagine the influence on previous Boston Calling headliner the Decemberists, just to name one band. And the National capped the first night with an even stronger set than its inaugural appearance, with dizzying visuals and guitarists Aaron (who curates the event) and Bryce Dessner gesturing to fans. Frontman Matt Berninger also plowed deep through the crowd during “Terrible Love” before the group closed with the acoustic “Vanderlyle Crybaby Geeks.”

Geeks of all stripes found their tribe in this year’s Boston Calling lineup, which drew 45,000 over the entire weekend, though attendance seemed to be less than half of that each day, short of sold out. Perhaps folks hold on to the image of City Hall Plaza as an unforgiving brick-and-concrete place, especially in hot weather. But it wasn’t that bad, apart from Saturday’s uncertain storm break. Even without the welcome video screens (one of which was lowered Saturday for the storm), the sightlines and the sound were fine in most spots. Sure, Boston Calling can be expensive if you’re only keen on seeing one or two acts. But when they announce next year’s lineup, hopefully more kids and adults will enjoy taking advantage of our city’s own major music festival.