The plot of G.I. Joe is simple. A group of elite paramilitary soldiers fights to stop an evil organization bent on world domination. The movie is an origin story, but not of the Joes, who are already established before the film begins. Instead, as the subtitle states, the film focuses on "The Rise of Cobra" and the rise to power of James McCullen, who becomes a major Joe villain. If you have seen the dozens of commercials currently promoting the movie, you have seen about 60 percent of this movie.
The acting is not going to win any academy awards, but is not intrusively bad. In short: Rachel Nichols is beautiful as the red-haired Scarlett, Channing Tatum is ruggedly handsome as the scarred Duke, Christopher Eccleston is evil as McCullen, Marlon Wayons is funny as Ripcord, Sienna Miller is sexy as the Baroness, and Dennis Quad and Adewale Akinnuoye-Agbaje are charismatically inspiring as the Joe's commanders.
But seriously, are you really going to see G.I. Joe for the Shakespearian acting or the riveting plot? Of course not, the movie is based on toys made by Hasbro. You want action, and the film delivers plenty of it. The Joes fight in the air, the sea, on the ground and under it. Once again however, Summers relies a little too much on CGI characters (though not as much as he did in the not-very-good Van Helsing). For example, I was not enamored with the (over)use of the Delta-6 Accelerator suits in the Paris chase scene. On the other hand, the character of Snake Eyes (played by martial artist Ray Park) was the perfect ninja superhero. (I should also mention that Park is producing an upcoming Snake Eyes comic with writer Kevin VanHook and artist S. L. Gallant).
As a father, the only note I will make about the action is that there is a lot of death and violence. For some reason, more people get stabbed in this movie than in a standard horror flick. That being said, a lot of the violence is against the mindless robot-like Cobra soldiers, which makes the action more like the many stormtrooper deaths featured in the various Star Wars films. That being said, you should decide on your own whether your children can handle it.
There are certainly nods to the toys and comic books, including a mod to the original G.I. Joe's, which had "kung fu grip" and "lifelike hair." They are also some major differences in characterization. Most notably, one hero has become a villain and one major villain ends up a hero. Another major difference is the addition of preexisting relationships between a lot of the character (these were all told through flashback, which was occasionally overused and interfered with the action).
To sum this review up, if you liked the Mummy, you will like this. (There are a few nods to the Mummy, including a base in Egypt and the fact that Brendon Fraser plays an uncredited role of a character that is a direct descendant of Rick O'Connel, the hero Frasier originated in the Mummy Franchise.) If you didn't like the over-the-top action in that movie, you will most likely not like G.I. Joe. And, if you are looking for a live action interpretation of the comics (created by the great Larry Hama), you will still be waiting when the credits roll. For those people, I recommend one the many new GI Joe series from IDW Publishing. If you are seeking to determine who will the Oscar for best picture, skip this. Otherwise, grab a big tub of popcorn and enjoy two hours of over the top action.
Now you know, and knowing is half the battle.