At age 33, " A Chorus Line" is a little too long in the "line" to still be considered a sensation. But it remains a singularly sensational theatrical experience.

With only 1975 workout clothes for costumes and the most famous mirror in mirror history for its set, "A Chorus Line" is still spectacular because of its pure physicality, groundbreaking choreography (for its time) and naked character vulnerability that remain unmatched by any major musical since.

The newest national touring production, inspired by the 2006 Broadway revival but (thankfully) unchanged from '75, is launching this week in Denver, though we're not much more than a quick final dress rehearsal before a higher-profile stop in Los Angeles.

"A Chorus Line" is the story of 17 dancers run not only through a grueling dance audition but a personally invasive psychological gauntlet. Their shrink is a "Voice of God" director who today would be spending more time in court than on choreography.

Based on interviews with actual dance gypsies, "A Chorus Line" was the original "Laramie Project." Michael Bennett and his team fused the dreams and intensely personal confessions of real wannabes into a physical and emotional endurance test that lasts two hours without intermission.

The signature song and dance is "One," and all it takes is a few notes for the crowd to burst into applause. But as exhaustively impressive as the dancing is, "A Chorus Line" remains most relevant for how many varied and believable characters it lets us know in such a short period of time.

That's because every one is real. This is a character study as precise in word as the dancing is in step.

There's Val (crowd favorite Natalie Hall), the homely girl who has bought herself the physical attributes nature denied her; there's father-of-two Don (Northern Colorado grad Derek Hanson, last here in the Arvada Center's "Best Little Whorehouse"); there's drag-queen Paul (a wrenching Kevin Santos); there's statuesque diva Sheila (Emily Fletcher) and a dozen more.

Most endearingly, there's Cassie (the intoxicating Nikki Snelson). She's the ex-girlfriend of omnipotent director Zach (Michael Gruber), a girl once considered a star but now a woman desperate for work — even "back in the line."

These 17 wannabes might as well be 1,000. They cut a swath across ethnicities, ages, orientations and attitudes, yet James Kirkwood and Nicholas Dante's deserving Pulitzer-winning script somehow manages to draw a portrait of the universal dreamer.

Most are long past the age when dreams like theirs are ever fulfilled, but at today's audition, ever closer to their last, they again will follow every directive and endure every humiliation. Only this time, a voyeur will publicly draw out their innermost fears, past failures and demons.

In time, a commonality emerges: adolescent humiliations; difficulties with parents; shared, lonely struggles to find a place in the world.

Combined with anthemic Marvin Hamlisch/Edward Kleban ballads like "At the Ballet" and "What I Did for Love," it doesn't really matter what your professional field is. "A Chorus Line" is for anyone who's had a dream — or not been picked for a team on the playground. It's a snapshot of its time, but it transcends time, and the world of dance.

What this cruel audition makes obvious is the utter randomness of it all. No matter what kind of promotion you seek, there are vagaries at play you can't control. Talent does not always win out. These dancers don't know what ethnicity or body type the director is looking for. Or how the individuals he chooses will look together to form one whole.

The ultimate paradox of life in the chorus is that you must have individual skills that will make you stand out in an audition — but once chosen, you must blend into an indistinguishable group so as not to detract from the star.

To the untrained eye, any of these dancers is good enough for Broadway. But some of them will never catch a break, and that's the whole cold, cruel point of the biz. I've often felt the director should choose a different eight every night just to elucidate that point. Then again, in its first staging, Cassie didn't get the job, and audiences wouldn't stand for it — so the script was changed.

While most will, and should, bow to this deserving, talented inaugural touring cast, this incarnation is only a few days old, and it's understandably not yet completely clean. "A Chorus Line's" reputation is built on decades of precision movement (down to every intentional misstep) and impeccable line spacing. This isn't up to Bennett's standards yet.

Pacing is also an issue — Thursday's final preview ran 10 minutes longer than scheduled. That will come in time. Maybe this week: They're making them do eight shows in five days, for crying out loud.

And believe it or not, they still haven't quite mastered the curtain call. Thursday's audience couldn't figure out when to stand for what turned out to be an abrupt and awkward ending. Given Denver audiences' rep for standing for a sit-in, it was shocking not to see anyone on their feet. It's not because they were unmoved, just confused.

Some will leave "A Chorus Line" humming a tune; others reliving high-steps in their heads; others contemplating real-life questions. Like, if you don't get what you want, what will you do with your life?

What more could you want from one show?