The 76-year-old director, under house arrest in his chalet in Gstaad, is among the early frontrunners for prizes at the Berlin film festival this year, although the 10-day competition has yet to reach halfway.
The political thriller based on a novel by Robert Harris is one of 20 movies vying for the Golden Bear for best picture, which Polanski won in 1966 for "Cul-de-Sac."
The fact that it is among the favorites is remarkable given that post-production was completed while Polanski was in a Swiss prison and, later, under house arrest.
"With this immensely enjoyable, satisfyingly convoluted thriller he demonstrates exactly why he is still a force to be reckoned with," Wendy Ide wrote in the Times newspaper.
"From the opening scene it is clear Polanski had complete control, whether or not he was behind bars when he finished it."
The United States is seeking to extradite Polanski to face justice after he fled the country in 1978 on the eve of his formal sentencing for unlawful sex with a 13-year-old girl.
Peter Bradshaw of the Guardian said: "This is his most purely enjoyable picture for years, a Hitchcockian nightmare with a persistent, stomach-turning sense of disquiet, brought off with confidence and dash."
Hollywood trade publications were more circumspect, however.
Kirk Honeycutt of The Hollywood Reporter described the film about a disgraced British prime minister loosely based on Tony Blair as "sleek" and "hypnotic," "but once the credit roll frees you from its grip, it doesn't bear close scrutiny."
Derek Elley of Variety was one of the few dissenting voices in Berlin:
"All the ingredients are here for a rip-roaring political thriller ... but ... Polanski simply transfers Harris' undistinguished prose direct to the screen and ... there's little wow factor in the revelations as they appear."
The Ghost Writer stars Ewan McGregor as a writer brought in to spice up the memoirs of an ex-premier (Pierce Brosnan).
The politician soon becomes embroiled in a bid to have him tried for war crimes, while the writer, who remains nameless, begins to uncover uncomfortable truths about the former leader and his wife, played by Olivia Williams.
Polanski is not alone in impressing critics in Berlin this year, with two other competition entries scoring strongly.
"If I Want to Whistle, I Whistle" is part of the "new wave" of Romanian film-making that has wowed festivals around the world in recent years.
It follows an 18-year-old young offender who is days away from being released from a correction facility. He discovers his mother, who abandoned him as a child, plans to take his brother to Italy, forcing him to take dramatic measures to break free.
Screen International wrote of its "outstanding quality," and the same publication was even more positive about "Submarino," a tough Danish drama which contains scenes of domestic abuse.
"Rarely has there been such a downbeat feel-good movie, but feel-good it is: Submarino works like an emotional massage, leaving the viewer pummeled but invigorated," Screen wrote.
The Berlin film festival awards ceremony is held on Feb. 20.
