After watching the The Mexican, I was reminded of all the roles Brad Pitt has played where he acts this loony high-energy individual (Snatch, Fight Club, 12 Monkeys). The Mexican features Pitt in a similar role.
The plot of The Mexican revolves around a gun (with the same name), which was crafted by a gunsmith specially for a nobelman's son so he (the nobelman's son) would marry the gunsmith's daughter. Over decades, the gun acquires a reputation of its own. While it is not clear what happened the day the gunsmith presented his gift, there is consensus that it resulted in great tragedy, making people think that the gun is cursed and therefore giving it great value.
Jerry (Pitt) is in charge of obtaining the gun, as a means of repaying a debt to Margolis (Gene Hackman), an organised crime boss. (The debt was incurred when Jerry's car crashes into Margolis' who ends up in prison when the police find a person bound and gagged in the trunk.) However, there are other interests here who also seek to possess the gun. Not only does Jerry have to contend with an assortment of thugs and goons who are after him and the gun, but his wife Samantha (Julia Roberts) doesn't make life easy for him. Even though they are in love with each other, she is not able to stop beleaguering him.
The acting by both the leads is excellent. Roberts plays a convincing almost-shrewish wife (over acting only slightly), and Pitt's Jerry invokes a lot of empathy not only for putting up with Samantha, but also in the way he manages to "Forrest Gump his way" through various predicaments. The cinematography is colourful and interesting. The humour is dry and witty, but for some reason The Mexican never completely clicked in this regard for me.
The Mexican is a decent film, worth renting or the matinee fare if there are no obviously better choices.