Casting Denzel Washington as a quietly spoken crime boss who shoots a man in the head before resuming conversation over a meal with the quip "Now where was I?" - there's something not quite right here, just as in the film, white cops furrow their brows at the thought of a black man who outsmarts the Mafia by selling pure heroin at bargain prices.

Are we meant to like this dapper smuggler, with his easy smile and love for his dear old mum? It's never quite clear whether the screen version of Frank Lucas does justice to the real life gangster, who peddled his super-strength heroin from Asia during the late stages of the Vietnam War under the brand name Blue Magic.

Ridley Scott's film is more about corruption and redemption than Goodfellas-style bloodshed; the cops are nearly all crooks, the exception being Richie Roberts (Russell Crowe). Crowe turns in a surprisingly watchable performance as a grizzled detective determined to nail the bad guy while coping with a failed marriage and trying to revive his career.

That sounds cliched, and the dialogue is occasionally clunky or moralistic. When you see Crowe making a crisp sandwich while the movie cuts to show Washington feasting with his family at Thanksgiving, it's not one of the director's brighter moments.

But despite the two-and-a-half hour running time, American Gangster rarely drags and all the cast put in compelling performances. Josh Brolin is particularly entertaining as a smarmy, gimlet-eyed detective, Trupo, who makes the mistake of getting a little too greedy for bribes.

If you're a fan of sleazy 70s movies, you'll enjoy the repetitive sequences of cars roaming through drab housing projects and girls shaking their 'booty' in dingy nightclubs.

The problem is that we see too much of junkies in New York's forlorn tenements and learn too little about the man who supplies them.

OUR RATING: three and a half stars out of five Thriller/Drama. Denzel Washington, Russell Crowe, Chiwetel Ejiofor, Cuba Gooding Jr, Josh Brolin, Rza, John Ortiz, John Hawkes, Ted Levine, Clarence Williams III. Director: Ridley Scott.