I don't think I ever realized how absolutely incredible Jamie Lee Curtis's acting is in the movie. (Her topless scene in TRADING PLACES was a formative mark on my young sex drive, so when I was eighteen the movie was all about OMG SHE DANCES SEXY IN HER UNDERWEAR AND ARNOLD KILLS GUYS.) But she's absolutely amazing. The sequence in the mirrored room, where she's interrogated by parties unknown to her, is extraordinarily grotesque from a human-relationships point-of-view; Helen Tasker's husband Harry (Arnold Schwarzenegger), whom she does not know is a superspy, has pulled a full-out knockdown raid on her, complete with shaped charges and men in body armor, because he suspects her of having an affair. (I had forgotten that Helen actually gets *hit on the head with a rifle butt* during that raid, after she shows enough cojones to fight and try to run for it.) Harry interrogates her using a voice-changer. It's a really horrible scene, and Helen is so likable that it's even worse. But Curtis transitions through a zillion absolutely believable emotions in that scene, and she's so good that you almost forget to be totally horrified. Because it's a ghastly situation, but OMG does she sell it. Jamie Lee Curtis plays Helen Tasker as a real person reacting to horrible things in a funny way, and even when you're supposed to laugh at Helen for her awkwardness Curtis plays it as a *human* awkwardness. She doesn't go over-the-top with it, and that's pretty impressive considering some of the things Cameron's script has her doing. (Consider the scene where she tries to fire a full-auto, gets her ass kicked by recoil, and drops the gun, whereupon it falls down the stairs and kills a shitload of bad guys. That's an invitation for us to laugh at Helen. It's not a sympathetic script moment. Curtis has a tough line to walk with her reaction, and she does it amazingly; she makes her cringing, mugging reaction funny, but doesn't overdo it. The script makes Helen look bad, but the actress makes her look human.) Curtis plays Helen as a real person, with real reactions, who's had the misfortune to get stuck in an over-the-top action movie.
By contrast, Arnold's Harry Tasker is the most colossal ass in the history of Arnold roles. I think part of this is because Arnold Schwarzenegger is playing him: the bit where Harry goes off the rails and starts ordering Helen's phone be tapped and lining up a no-knock raid needs to be horrifyingly funny if it's going to play as anything other than grotesque. The audience needs to see that Harry is going totally off the rails, and be appalled -- laughing in horror, rather than sympathetically. The problem is that Arnold playing off-the-rails is exactly the same as Arnold playing hard-charging hero. (The Governator does have one very good acting bit, when he initially comes to suspect the affair; he walks along numbly and slowly, almost getting hit by a bus, and it's a little surprising how affecting it is to see Arnold in a state of almost believable vulnerability. Enjoy it, because it's gone shortly, and he's back to kicking ass.) Also, Schwarzenegger is famously narcissistic (witness even his political career, where he started trying to grab power for himself to cut California's budget; when he failed, he turned around and started spending spending spending so people would like him), so that trait probably handicaps his ability to effect the role: he can't play Harry's reaction as horrible, because to him it isn't; he enjoys Harry's flaunting of horrifying power, and plays it in a way that he expects the audience to enjoy it, too. It's more than a little disturbing.
Also: the stuntwork on the movie is even more amazing than I remembered. That money sequence, with the limo and helicopter? WOW. Farking incredible work by everyone involved, especially the helicopter pilot.