Stands and falls on one's attitude to Newman's impersonations and general persona throughout the film and, indeed, the film seems to be too in love with Newman qua actor to let anything happen. Whilst Newman is obviously famous, the level of star quality required for this kind of vehicle hasn't lasted through into 2022 despite his salad dressing empire, so it lands more than a little strange today, leading your subconscious to justifiably ask: "why is he being indulged so much?"
The comedic turns don't fit with the surrounding technicolor—cum—noir aesthetic, and ends up as misfired attempt to distance itself from black-and-white classics. The fingerprints of the (far superior) Bond franchise seem to be over this as well: wisecracks and fantastic locations plus a physically invulnerable henchman and reckless driving of a sports car? Sounds familiar. And not to mention Newman's coldly aggressive sexual advances towards a woman (who is almost too 'conveniently' his wife in a 'surprise' turn), a scene that the film's tone rewards.
Synopsis: Harper is a cynical private eye in the best tradition of Bogart. He even has Bogie's Baby hiring him to find her missing husband, getting involved along the way with an assortment of unsavory characters and an illegal-alien smuggling ring.