Monsters vs Aliens contains an interesting mix of contradictions. It’s shot and animated using up-to-the-minute technology but in the service of a decidedly old-fashioned story; it’s steeped in the 1950s B-movie tradition, but its premise is decidedly feminist. Even the use of 3-D technology is complex, simultaneously reaching back to the gimmicky 3-D films of the 50s while hoping to pull modern audiences away from their computer screens and back into theaters.

Those juxtapositions are the most challenging and interesting thing about the film, which is mostly a paint-by-numbers action yukfest. This level of harmless fun and limited ambition is par for the course for a non-Pixar animated film these days (Kung-Fu Panda was a recent exception).

Reese Witherspoon does a nice job voicing 50-foot-tall Ginormica (aka Susan Murphy), a bride-to-be who’s in the wrong place at the right time when a radioactive meteor strikes. Her coming to terms with her newly-acquired powers is played as a feminist allegory and it’s a stirring moment indeed when she decides to fully embrace her destiny.

A strong voice cast (including Hugh Laurie, Paul Rudd, Will Arnett, Rainn Wilson, Jeffrey Tambor, Amy Poehler and Ed Helms) is largely wasted. The exceptions are Kiefer Sutherland, doing a comical Southern accent as a military general straight out of Dr. Strangelove (it’s nice to see Jack Bauer have some fun), and Seth Rogen, whose blob of indestructible brainless blue goo (named B.O.B.) is the funniest thing in the movie.

Also, while the payoff isn’t what it could be, it’s hard not to root for a film when the opening credits proclaim “and Stephen Colbert as The President.”