‘Vegas Nocturne’ hasn’t jelled at Rose.Rabbit.Lie.

Take in the whole menu. Enjoy as much of it as you can sample. But remember, you’re paying for the atmosphere.

Since Rose.Rabbit.Lie. is part restaurant, a few dining cliches prove apt here, including the fact that ordering a la carte is almost never your best deal.

The good news-bad news is that The Cosmopolitan of Las Vegas has created something different, to the point that it doesn’t seem to have it all sorted out yet.

When you add up the sum of the parts, Rose is the entertainment alternative a lot of us have been waiting for. But most consumers will only buy it in parts.

The themed restaurant/show/nightclub creates a hidden, retro speakeasy full of characters who, we are told if we pay attention, rebuilt their Russian family mansion in Las Vegas after the 1906 San Francisco earthquake.

You will eventually see them all perform, whether it’s a spontaneous song delivered on top of the bar, or in the separately ticketed show, “Vegas Nocturne.”

At one point during the early “Nocturne,” I dashed to the men’s room while David O’mer distracted the ladies with his acrobatics above an antique bathtub, only to discover another splashy act — two women in a Champagne glass — in the adjacent barroom.

Another side trip during the 10 p.m. edition of “Nocturne” found the barroom exploding with the tap-dancing Scott Brothers, who, of course, also ended up on top of the bar.

The environmental theater begins early as you nosh on your small plates and sip your craft cocktails (or $2,728 bottle of 1953 Vega Sicilica Unico, if you’re ahead at the tables). There’s that guy in a red velour suit sitting alone in front a chessboard, or a musician, Robert Tiso, playing an antique glass harmonica.

By 7 p.m., a scrim reveals the live combo in the adjacent bar as they strike up loungey covers of “Get Lucky” and “Royals.” And at 8 p.m., some diners cross into the main room to join the rest in the tiered seating that circles the small stage for the first performance of “Nocturne.”

And that’s where the trouble begins.

“Nocturne” hasn’t yet caught up to its environment. Although it’s staged by the same producer of “Absinthe” at Caesars Palace — Ross Mollison’s Spiegelworld — it plays more like a competitor’s knockoff.

Both shows share the comic vision of director Wayne Harrison, who has an amazing knack for serving up slapstick and raunch with a dry, highbrow wink, and for creating transitions to unite a series of otherwise random specialty performers.

But “Absinthe” consolidates its point of view through a central character, The Gazillionaire, a seedy ringmaster who sets the tone for a night of fun slumming.

Here the surroundings are more upscale, and our cast of madcaps younger, less cohesive, and way more over the top. At times the comedy seems more like a community theater version of “Absinthe.” It may be the creators thought The Cosmo’s younger demographic prefers broad mugging to wit. Or it could be some roles were cast less on acting ability than the specialized skills some characters are revealed to possess.

Our host this time is Alfonso (Lorenzo Pisoni), a dashing straight man who lets his crazy family circle around him. Of them, Kasey Wilson is the only one to create a full comic character in sister Beverly, an ineptly high-strung, ’60s-sitcom kind of gal.

But we only meet them after a kind of tonal fake out with the first specialty act. Lara Jacobs Rigolo, “the Balance Goddess,” picks up palm ribs with her toes to assemble this large exoskeleton above her head, as singer Chrissi Poland croons Enya-like vocals for a full 15 minutes. Sound more like Cirque du Soleil? Well, Rigolo used to do this for Cirque.

More of what “Nocturne” becomes is embodied by Captain Frodo, “The Incredible Rubberman,” a dislocation contortionist who manages to pass his whole body through a tennis racquet. It’s funny — “But more about me, less about Jesus,” he proclaims at one point — but more than a little disturbing.

More of the show is pleasantly forgettable, modern-Vegas variety: a sexy adagio hand-balancing couple, a fire-breathing burlesque dancer, or Julien Posada dancing on a high wire, which is actually a “low wire” only a few feet off the ground in this low-ceilinged room.

But that’s just the 8 p.m. show, or “canto” as it’s pretentiously known here. If you go home now, I’d say you would have done just as well with the “pop-up” acts in the bar, or hitting the discount booths for “Absinthe” tickets.

But then, a funny thing happens: the 10 p.m. show.

Some of the opening weekend’s invited audience had the chance to stick around. For now — and this could soon change — regular showgoers cannot do the same without buying two tickets.

Too bad, because the later show somehow makes the early one better. It’s almost as if “Nocturne” is really a two-act play with an intermission. (And there is a “third act” at midnight, which turns the joint into a club for the rest of the night.)

The hosts are back, but the atmosphere is looser. We see return visits by some of the players, including Piff the Magic Dragon (John van der Put), a sad-sack little magician in a ridiculous dragon suit who performs with a Chihuahua named Mr. Piffles. “It’s not David Copperfield,” he reminds us.

Piff’s second round was more “the right amount of wrong” (as he name-checks host property’s tag line), when an audience recruit is coaxed into putting a gun to Mr. Piffles’ head, or the cute little doggie is purportedly shot out of a cannon.

The second show is a lot more naked too, when we see the family “accountant” (Leah Shelton) do a striptease vanishing handkerchief act that isn’t David Copperfield either.

I loved that she stripped to the Henry Mancini movie theme “A Shot in the Dark.” Or that another exotic (Emilia Arata) performed in a clear orb while singer Butterscotch vocalized Gershwin’s “Summertime” with impressions of musical instruments, while Tiso played a glass harp — wine glasses filled with liquids.

If you too are excited by such things, give Rose.Rabbit.Lie. and “Vegas Nocturne” time to figure out its price structuring, and to let its winning ingredients ferment into just the right combination.

Hopefully, it won’t take as long as that ’53 Vega Sicilica Unico.

Contact reporter Mike Weatherford at mweatherford@reviewjournal.com or 702-383-0288.