All the signs were good: The trailer flashed with overambitious conspiracy that – if lacking in substance – would at least have style and celebrity to spare; seasoned smart-crime director/screenwriter Joe Carnahan (“”Narc””) split from “”M:I III”” over “”creative differences”” (and the replacement sucked); and of course there was Alicia Keys, possibly as a lesbian, in skanky hitwoman garb. Etcetera.

And Carnahan hasn’t failed to turn out the promised Guy-Ritchie-meets-Tarantino feast – not since “”Rat Race”” have so many illustrious, prize-eyed characters flocked to one alleged jackpot, and the mind-numbing bloodbath of “”Smokin’ Aces”” gives “”The Departed”” a run for its money. Framed in richly saturated panorama, Lake Tahoe – Nevada’s lesser-used casino hotspot – sets a sparkling stage of retro cools and bay windows, most vividly in Buddy “”Israel”” Aces’ coke-laced penthouse suite on top of the Nomad hotel.

After deciding to aid the feds in locating affiliate mob boss Primo Sparazza, the extermination of the sleazeball illusionist (Jeremy Piven, quickly besting Norton, Jackman and Bale) is soon worth $1 million. The offer lures a grab bag of crazed assassins, including a feminist and a vixen, a scar-faced bounty hunter and a pair of bail bondsmen. Meanwhile, the FBI (fronted by Ryan Reynolds and Ray Liotta, backed by Andy Garcia) must keep Aces alive for reasons unexplained until Garcia’s dizzying flashback fill-in at the movie’s end.

Perhaps most memorable among the competition are the three comic-relieving Tremor brothers, who make a raging redneck entrance in their flame-painted ’89 Cadillac DeVille, bumping some eardrum-shattering thrash metal: After screeching to a halt, one guns down the only characters we’ve even begun to identify with, one pens himself a Hitler moustache and the last finishes off a greasy chicken leg to kneel at Ben Affleck’s carcass and make his lips mouth forgiveness.

But following the cracked-out introductory sequences – an expected overdose of smart talk, f-bombs and still-shot nametags (complete with steely nicknames) – the film’s second half takes a spiraling nosedive into a black hole of confused identities and untraceable plot twists, making for some sweet elevator death sequences and not much more.

To match his successfully novel character choices – including a campily pimpled bellboy – Carnahan did get creative with weaponry and causes of death. The Tremors break out their chainsaw for some pink mist, flaming feds fly across the screen and Aces’ assistant’s face gets made into a mask. Sweet.

Then something weird starts to happen. Dramatic symphony swells begin to seep in (interrupting an otherwise killer soundtrack, stacked with GZA and the Stooges), illustrating up-close tear-rolling shots and prolonged emotional interaction. Yeah, so like 20 people just died, but were we really supposed to be taking it seriously that whole time? Should we actually feel bad for Alicia Keys’ female admirer while she mournfully watches her object of lust being baby-carried away from the wreckage by rapper Common? Hopefully, the whole thing is a joke and the answer is no.

Opens in wide release Jan. 26.