I fully admit I am not the biggest Demi Moore fan in the world. As a matter of fact, she's been in some of my least favorite movies of the decade (A FEW GOOD MEN, INDECENT PROPOSAL, THE SCARLET LETTER, THE JUROR, STRIPTEASE), and she really hasn't been good in any of those. But she did win me over in this movie, because she lives up to her character's line, "Look, I'm not trying to make any sort of statement here." And she isn't. Instead of letting vanity get in the way, or injecting pathos, she lets her actions speak for her, just like her character does in trying to win acceptance as a SEAL. The haircut scene is a good example; though it's directed with cinematic flourish, she does it matter-of-fact.
Moore's performance is one of the two performances that elevate this from your standard grunts-become-soldiers movie. The other is the riveting Viggo Mortenson as the Master Chief, who's the drill instructor. He doesn't play the role as a sadistic tyrant, but rather as a subtle manipulator who gradually recognizes Jordan O'Neill(Moore) is someone worth taking seriously. He also avoids going for pathos.
The movie is best when it concentrates on the training. Ironically, making just a standard grunts-become-soldiers movie makes its message work, because like O'Neill's superiors, we take her seriously because she becomes no different than anyone else. The beginning is bad, and the climatic battle at the end is overblown, which weakens the movie. Still, it's worth a look, and I maintain Moore was only given a Razzie Award for this movie and performance because of her past work, and the naysayers really weren't paying attention to her performance here.