I sometimes wonder when audiences will demand more than just a mediocre animated film. Then I look at the opening weekend figures for Monsters vs. Aliens, and I keep on wondering. This latest release from Dreamworks Animation Studios is not a bad film, just a superficial one. Behind the astonishing animation is a hollow plot with morals that are tired and worn from overuse. If the idea of an outcast learning to appreciate his/her uniqueness while searching for acceptance feels like déjà vu, it's because this is the same formula that Dreamworks has stretched to encompass all of its animated releases.

Now here's Monsters vs. Aliens, which chronicles the plight of Susan (voice of Reese Witherspoon), a bride-to-be who, just before delivering her vows, is hit with an asteroid and grows to the height of a skyscraper. Her frightened fiancé, Derek (Paul Rudd), then runs off as military troops arrive to sedate Susan and transport her to a top secret underground holding facility. There she is dubbed "Amazonia" and placed in a holding cell with four other "monsters": The Missing Link (Will Arnett), a narcissistic amphibian with a pension for scaring beachgoers; B.O.B. (Seth Rogan), a brainless blob created at a food testing laboratory after a ranch dip experiment went horribly wrong; Dr. Cockroach (Hugh Laurie), a former scientist now transformed into a talking insect; and Insectosaurus, a mutated caterpillar that towers over all the other monsters, including Susan. After an alien ruler (Rainn Wilson) sends a robot droid to scour Earth for a lost element -- one that might transform an ordinary woman into a giant, perhaps? -- the President of the United States (Stephen Colbert) agrees to release the monsters under the care of General W.R. Monger (Keifer Sutherland) to combat an alien invasion.

Although it culminates with a final battle between the monsters and aliens, the film is squarely focused on Susan and her desperate struggle to find acceptance in a world that is terrified of her. As seen in DreamWorks' Shrek, this conflict can work. Here, however, it doesn't because the screenwriters (five are credited) write Susan as a wishy-washy leading character. In her scenes with the other monsters, Susan is shown gaining confidence and becoming independent, but these scenes are bookends for the ones where she is still pining for Derek as a needy, oblivious, emotionally unstable mess. There's an unnecessary scene halfway through the film involving Susan, as a giant, being dumped by Derek on the grounds that he needs to focus on his career, not on helping her back to normalcy. This is a sorely undesired detour that the film takes to remind the audience that Derek is self-centered and that Susan doesn't need him; trouble is, the opening wedding sequence where Derek leaves her at the alter sufficed both these points just fine. It leaves the audience to wonder if Susan was that naïve not to notice that Derek was a slime ball (figuratively speaking, that is) up until the point where he officially breaks it off with her. Of course being that this movie is aimed at children, chances are kids won't be wondering such things, but I can't imagine a lot of them will be clamoring for Susan action figures after seeing this movie. I know I went for the B.O.B. one myself.

As for the rest of the animated cast, their roles are voiced by the likes of Seth Rogan, Will Arnett, and Rainn Wilson, so the characters being secondary and comedic comes as no surprise. None of the supporting characters are particularly deep and are each limited to one characteristic. Even the alien ruler is compressed into a few minutes at the beginning and end of the film; otherwise this movie could be called Monsters vs. Robot Probes, though I imagine that title wouldn't sit well with parents. Since Susan is the main attraction here, none of the characters show even a hint of promise for the evident Monsters vs. Aliens sequel; B.O.B. comes closest to having more story to tell by having a relationship with a plate of Jell-O. For the sequel I suggest answering a few questions, like how the two will mate and which of them is the smartest.

Though the characters remain one-dimensional in the script, the voice acting at least supplies each character with its own distinct voice and is surprisingly good. Previously mentioned Rogan, Arnett, and Wilson are what can be expected from their live-action roles: quirky and imaginative. Two of the biggest surprises in the film come from Keifer Sutherland and Hugh Laurie. Sutherland is the more recognizable of the two but not by much. He sounds a bit like Tommy Lee Jones if he were attempting to imitate R. Lee Ermey. Laurie is virtually unrecognizable as Dr. Cockroach, particularly to those who are used to hearing the Western accent he uses for television and movies here in the States. Sutherland and Laurie do not provide the film's biggest laughs but do provide the characters with a bit more personality than someone like Rogan, who just sounds like Seth Rogan.

Visually, the film is absolutely stunning. From the opening shots of outer space to the detail of the fur on Insectosaurus, no expense was spared in the animation department. I would have liked it, however, if the human characters had been given equal treatment. While it's great to see things like B.O.B. digesting a whole ham (complete with disintegration), it's unfortunate that the human characters can move their lips in what seems like only two animations. It gives the human characters a disconnected feeling from the rest of the cast -- a prominent fault considering that Susan is one of those human characters interacting with monsters that are much better animated than she is. Nevertheless, the film is a visual treat. Bright colors permeate the screen and attention to detail is astounding, from textures to contours. Each character moves differently from the others and never looks like a carbon copy. The visuals are thoroughly enjoyable all the way through.

If only the plot weren't so tired and worn, Monsters vs. Aliens would be a much better film than it is. Despite a strong showing from the cast of voice actors and the superb visual effects, Monsters vs. Aliens is just another lesson-toting animated film from a studio that is working in familiar territory. It's enjoyable for the hour-and-a-half that it takes to go through the motions of other Dreamworks films, but it does not have the staying power of other Dreamworks classics.