Let me start off by saying this movie isn't as good as the previous films in the franchise. I would venture to say that Terminator 3 was better than this. I'm a pretty big fan of the franchise, though I never really got into the TV show. Mostly because it departs from the timeline set up by the films. I've also seen the mini-movie Terminator 3-D at Universal Studios. First off, Salvation is rated PG-13, while all the others are rated R. Typically, this tactic is in a futile attempt to draw a larger audience (as R rated films restrict teenage viewers). Featuring Christian Bale as John Connor, Bryce Dallas Howard as Kate Connor, Sam Worthington as Marcus Wright, Anton Yelchin as Kyle Reese, and featuring Helena Bonham Carter, Common, and Roland Kickinger as the T-800, complete with a CG-mapped Arnold face.
In the year 2018, the machines (or more accurately humanoid robots equipped with guns) have dominated the world, and the remaining humans either hide or fight back as the Resistance. John Connor, now in his early 30s, is a commander of sorts. Many higher-ups in the Resistance don't believe he's the true prophet, although many people do. He encounters Marcus Wright, a man executed for murder in 2003, mysteriously up and around. Turns out, hey-oh, he's a cyborg! Cyberdine (a subsidiary of SkyNet or some such) harvested his body for science, and genetically engineered him to be mostly machine. There are lots of robot fights, explosions, driving around while robots fight and there are also explosions. Christian Bale uses his Batman voice, and Bryce Dallas Howard's character is pregnant, though never commented on, addressed, or mentioned whatsoever.
There are lots of little nods to the franchise throughout the film. Most of the robots are familiar, and there are loads of new ones (including ones that look like motorcycles, ones that look like sharp eels, and ones that look like humans. One of them even looks like that guy from Avatar, before he becomes a 12-foot Smurf shaman, or whatever. That's a review for another day. Someone also says "Come with me if you want to live!" which is almost always a good line. According to the trivia on the IMDb, even Kyle Reese's Nikes are similar to the ones that the "future" Kyle Reese wore in the original Terminator movie. However, extreme anal-retentive attention to detail does not a great movie make. The first Terminator film was directed by James Cameron, the man who directed two of the top-grossing films of all time, Acadamy and Golden Globe winner, etc. etc. etc. McG directed... Charlie's Angels. You can see where I'm going with this.
Most critics agree that Sam Worthington's performance is one of the best in the film. It's also nice to see Anton Yelchin, whom I primarily know from Charlie Bartlett and Star Trek. Supposedly, Yelchin studied Michael Biehn's performance as the original Kyle Reese to mimic his mannerisms and movements. He gives an intense and heated performance, a teenage boy who thinks he's tougher than he is, idolizes John Connor (his own son, crazily enough), and displays intelligence and intensity without much control. Worthington was an unknown before this film, though he was working with Cameron on Avatar first. Cameron recommended Worthington to McG for the role of Marcus Wright. Between this and Avatar, and the upcoming remake of Clash of the Titans, I expect to see more of him in the future. Bale gives a typical performance, I'm sorry to say. Not that he's awful, or anything. He was just like a dirty Bruce Wayne with his Batman's voice, though it was interesting to see the character of John Connor as an adult. Bryce Dallas Howard gives a decent performance, though her character (or perhaps herself in real life) is pregnant, which I would assume could be a bigger plot point given that it's John's child. However, it's never mentioned, alluded to, or acknowledged in any way. Oh well, I guess.
It's entertaining, though, which is better than nothing. It's worth a rent, and is good for some pretty crazy action scenes, good effects on the machines, and an interesting look at the future that Linda Hamilton spent two movies trying to prevent. I give it three and a half robot heart transplants out of five, or three and a half fake computer-generated Arnold Schwarzenegger robots out of five.