Cheers rang through TD Garden as an ominous hourglass appeared on screen along with a 10-minute countdown timer slowly ticking away as fans eagerly awaited the start of Panic! At The Disco’s Boston show on Sept. 28. As the seconds ticked to zero, the lights dimmed and smoke began to billow out from the stage as a nervous buzz crept over the crowd. The tension broke as the band’s iconic logo flashed on stage while a camera followed frontman Brendon Urie backstage through the opening bars of “Say Amen (Saturday Night),” before emerging, clad in all black, to the roar of fans screaming along as he sang out “Oh, It’s Saturday Night.”

Despite the Wednesday night time slot, the crowd brought the energy of a weekend performance cheering and singing along through some of Panic! At The Disco’s greatest hits over the first six tracks on the setlist. The opening song was followed up by high energy crowd-pleasers “Hey Look Ma, I Made It” and “Don't Threaten Me With a Good Time.” But even these high-energy tracks couldn’t top the sheer cacophony of 19,000 people unapologetically screaming along as Urie belted out the cathartic “if you love me let me go” while singing his 2013 hit “This is Gospel.” The band closed out Act I of the concert with “Emperor's New Clothes,” leaving fans in darkness as Urie disappeared from the stage.

Almost everything about Panic! At The Disco has changed since the release of the band’s debut album “A Fever You Can't Sweat Out” back in 2005. Three of the band’s four original members left the project, and after years of shuffling, the Panic! moniker has come to describe Urie as well as a changing cast of “touring members.”

On the “Viva Las Vengeance Tour,” Panic! At The Disco takes a big risk, playing the entirety of their newest album of the same name from front to back in order. No pauses. No breaks. No interjections.

It’s a risk that not only leaves the show with an hour-long stretch without any of the band’s greatest hits, but also leads to a natural comparison between the band’s older, darker sound and their new brighter image. Something Urie leans into, swapping out his black rhinestone jacket for a brightly colored suit jacket when remerging for Act II.

The decision garnered mixed audience reactions. Particularly, given that “Viva Las Vengeance” was not a well received album (though it’s not nearly as bad as former emo kids on TikTok would lead you to believe). For casual listeners, or even just hardcore core fans who prefer Panic!’s older sound, the contrast between the earlier crowd-pleasers and “Viva Las Vengeance” was stark. As one concert-goer poignantly put it, “I’ll pee during Viva Las Vengeance.”

But more than anything, the setlist was indicative of where Panic! At The Disco’s priorities lie. With 17 years in the music industry and dozens of hits, Panic! At The Disco has reached the point where not everything the audience wants can make it into the show. And while playing the band’s newest album in its entirety may not be a popular decision among casual concert-goers and older fans, it demonstrates an admirable commitment to Panic! fans who have remained dedicated through the band's evolution.

One thing that was constant across the three acts was the incredible production and stage design. Lighting played a key role in facilitating the transitions between acts, offering gorgeous visual cues onstage to complement both the moodier tone of Acts I and III as well as the blinding brightness of Act II.

And while the setlist is unconventional, not even the hit-or-miss tracks on “Viva Las Vengeance” can fetter Urie’s pure vocal talent. His ability to ascend through an ever-rising vocal range continues to impress, even as the constant high-pitch notes border on grating.

To the relief of many, Urie again disappeared from the stage as the final notes of “Do It to Death” rang through the venue, marking the end of Act II and promising a return to Panic! At The Disco’s greatest hits. When Urie returned to the stage, now wearing a white jacket, it was to sing “Girls / Girls / Boys,” in a celebration of bisexuality as rainbows bathed the stage, and audience members used their flashlights and colored pieces of paper to create a rainbow sea.

Through the end of the concert, it was a non-stop string of Panic!’s best tracks including “House of Memories,” “Nine in the Afternoon,” and “Death of a Bachelor.” No one in the audience missed a single word while singing along to “I Write Sins Not Tragedies” — the uncontested highlight of the night. Finally the show ended with performances of “Victorious” and the ever optimistic “High Hopes.”

It’s said that the only things people remember are first and last impressions. With a strong start and triumphant finish, that was certainly the case with the “Viva Las Vengeance Tour” as audience members filed out of TD Garden smiling from ear to ear.

—Staff writer Jen A. Hughes can be reached at jen.hughes@thecrimson.com. You can find her on twitter @JenHughes_