When an alien invasion threatens Earth, who you gonna call? Gelatinous ooze? A mad scientist-cockroach-man? A gigantic apprehensive woman? How about all three — and then some!

In DreamWorks’ new animated film, “Monsters vs. Aliens,” a woman named Susan Murphy (Reese Witherspoon, “Walk the Line”) is hit by a meteorite on her wedding day, causing her to grow to a gigantic size. Unable to live in the outside world anymore, Susan is taken away into government custody by General W.R. Monger (Keifer Sutherland, “24”) and renamed Ginormica. She then meets a group of other monsters, including blue goo without a brain named B.O.B (Seth Rogen, “Knocked Up”), a mad scientist who happens to be part bug named Dr. Cockroach (Hugh Laurie, “House”), a century-old sea creature named The Missing Link, and a giant bug that towers over Susan, named Insectorsaurus. Not long after Susan arrives, an alien named Gallaxhar (Rainn Wilson, “The Office”) threatens to invade the world and, after a not so helpful encounter with the incompetent president (Stephen Colbert, “The Colbert Report”), it is up to the monsters to save the day.

“Monsters vs. Aliens” is a movie that will best be experienced in 3-D. The visuals are phenomenal, and aside from a few of the clich? 3-D gags of things “popping” out at the audience, it is a wonder to see. It gives a moviegoer the feeling he or she is really there, and it’s a fun experience. The action in the movie is also exceptionally well done, and this will be something that kids will especially enjoy.

The movie also has many funny moments, mostly from B.O.B, Gallaxhar and the president. And fortunately for parents dragged to the theater by their kids, the humor is for everyone. For the kids, there’s the juvenile, silly humor, and for the adults, there’s the slightly more sophisticated humor that comes from pop culture references. From the president trying to make contact with the alien (featuring references to “Star Trek” and “Close Encounters of the Third Kind”), to the monsters themselves (“Attack of the 50 Foot Woman,” “The Blob,” “Creature from the Black Lagoon” and so on), humor transcends age and makes a “kids movie” a lot more appealing.

The film features an all-star cast that really shines through their appropriately casted on-screen personas. Colbert’s role as the president is a real treat, as he really delivers the incompetence and humor well. Also, Rogen pulls off playing brainless B.O.B fantastically — and most of the laughs come from his end. Also, Wilson as Gallaxhar is especially entertaining, and he plays his role splendidly.

Although the film has the humor and visuals to entertain, it lacks the heart we’ve seen in other DreamWorks films like “Shrek,” and the writing and storyline leaves something to be desired. The main character of the film is Susan/Ginormica, and her story, while an attempt at being heartwarming, is mostly clich? and uninteresting. The plot, in general, follows the clich? “main character has a change in life, she wants her old life back, she realizes it wasn’t so great and learns to enjoy the change and her new life.” And we’ve all seen that before.

The writing is one of the main reasons the film lacks the heart and depth it needs to be a classic animated film. With Susan/Ginormica as the main character, the audience should be feeling for her and her story line should be a big part of where the heart is. But in actuality, the audience doesn’t and therefore, the heart isn’t there. Perhaps the film should have focused more on the secondary characters, like B.O.B, that were far more entertaining, and it may have gone over better.

Overall, “Monsters vs. Aliens” is an entertaining trip to the movies, but only if you pay the extra three dollars to see it in 3-D. Prepare to be entertained for the time being, but if people are expecting to see a deep, heartwarming film along the lines of “Shrek” or “WALL-E,” they will be sorely disappointed.

So “ooze gonna save us,” as the tagline asks? Well the storyline certainly can’t save it, but perhaps the 3-D will save this entertaining but shallow film.

2 1/2 stars out of 5 for 2D.

3 stars out of 5 for 3-D.