I won't say that August Rush is the worst movie I've seen in the last year (at least), not because it isn't but only because I'm too tired having torn apart Dan in Real Life to have the energy to expound on all the bad choices made by the film's makers. (Excepting, perhaps Robin Williams's sideburns; I'm hard pressed to decide if his costuming was meant to overtly reference Brokeback Mountain and Midnight Cowboy and thus make implicit the character's gay-menace subtext or whether, given the film is essentially a reinvention of Oliver Twist, it is only supposed to get us as far away as possible from Fagin's Jewish identity and the implicit Jew-menace subtext.)
I will say that I can't think of a film since A Thin Red Line that drags on longer after you know what is going to happen. (I actually caught myself straining for glimpses of George Clooney in the Central Park crowd until I realized I, not August, was having a flashback.) I'm not sure whether or not to blame that on the writing, directing, or editing. I want to say the latter, as the film is perpetually building to montage moments over song-track serenades only to abruptly come to a screeching halt in order to start another. I guess this is meant to build tension (as opposed to merely make the film longer), but instead it just builds sluggishness. We're told repeatedly that these characters are desperately searching for each other, but they sort of slog through the film with a slothful confidence that if they wait long enough the movie they know they are in will end and they have no responsibility (beyond turning to the next page of the script) for moving their story along.
Freddie Highmore has a quiet intelligence and (miraculously for this film) the sense to avoid mugging (mostly) for the camera that allows him to escape from a sentimental shlockfest with his dignity intact. (Stack him up against Haley Joel Osment in Pay It Forward, and you'll see the difference between being in a bad movie versus being of one.) Terence Howard glides around the periphery of the action, and I'm uncertain whether he is supposed to be invoking his cop character in The Brave One or one of the angels in Wings of Desire. Certainly the sadness that Howard conveys (primarily through his low voice) plays against our cultural stereotypes of the big, angry black male and hence makes his characters memorable and seem a lot more varied than they really are. That's not a knock on him as an actor, though. The truth is that his performance, like Highmore's (and, really, I would even argue Williams's, though I don't like it) evidence an actor who knows (either deep down or straight up) that there's just nothing to his character in the script and it's up to him to make him real through performance choice and character mannerisms. While I always appreciate a professional giving it a go rather than phoning it in, in this case (ironically, since the subject is music) the independent choices the actors make for the characters clash, and so each seems to be inhabiting a different movie. (I started to say a "different world," but, again, these characters don't live in a world, they are characters who know they are characters in a movie rather than characters who think they are people in a world.)
For reasons I cannot fathom (perhaps because the film made me think of a parent searching for a child) the last paragraph and the distinction between characters who are people versus who know they are in a film made me think of Luc and Jean-Pierre Dardenne's 1996 masterpiece La Promesse. In it, Jeremie Renier as Igor spends a considerable amount of time trying to find a child. The contrast between these two films is a master illustration in the difference between plot as a bunch of stuff that happens and plot as the framework through which character is revealed and developed.