When Paramount/Dreamworks brought some footage of Monsters vs Aliens to Butt Numb A Thon in December, they made a bold choice: they would give the audience the full range of the movie by showing both the best and the worst scenes in the film. Walking out of that presentation I believed that Monsters vs Aliens would be another Shrek – a pop culture filled, reflexive reference laden piece of crap.

I was wrong. Monsters vs Aliens is actually quite good. I don’t want to oversell it – the script is still a draft or two away from being something really special – but Monsters vs Aliens manages to be charming, fun and even exciting. It certainly made my mouth water for a legitimate American giant monster movie. And no, Cloverfield doesn’t count. A giant monster movie where we can see the monster.

The premise of the film is simple – monsters exist, but the government has been rounding them up and hiding them from us for 50 years. Locked up right now are: Dr. Cockroach PhD, a mad scientist who turned himself into a roachman with a Vincent Price mustache (think The Fly); The Missing Link, an unfrozen fishman who terrorized beaches during Spring Break (think The Creature from the Black Lagoon); B.O.B., a genetic experiment gone awry that is a single eyed blob with no brain but a sunny disposition (think The Blob), and Insectasaurus, a grub that was caught in an A-Bomb test and is now a 200 foot tall caterpillar thing (think Mothra). Enter into this secret prison Susan, aka Ginormica, a woman whose close encounter with a meteor on her wedding day turns her into the 50 Foot Tall Bride (think the 50 Foot Woman).

That’s a set up for a sitcom, though, not a movie. It turns out that the meteor that hit Susan endowed her with vast cosmic energies that a space baddie named Galaxhar needs to be all-powerful. He comes to Earth looking to get the energy back, and thus the title now makes sense.

There’s some great stuff in the film; a giant robot rampaging in San Francisco is played with just enough comedy beats to keep the movie funny but is shot in a way that makes it feel like a legit action/giant monster movie. And the relationship between the monsters is amiable, if a little too Saturday morning cartoon (nobody has a problem with each other; the only emotional conflict is between Susan and her almost-husband, played by Paul Rudd). The voice cast – Hugh Laurie as Dr. Cockroach, Will Arnett as The Missing Link, Seth Rogen as B.O.B and Reese Witherspoon as Susan – are uniformly excellent, and there are a number of cameo voices that are also great. The movie’s voice cast is a cool comedy who’s who. The animation is solid, with Mad Magazine-inspired character designs and some really terrific giant monster stuff (a scene where the Golden Gate Bridge collapses is so Toho as it should be in the 21st century it almost made me clap). And the 3D is INCREDIBLE.

But all of those good things never seem to be more than the sum of their parts. The story is kind of flat, and feels like it might be missing an action beat (there are two big set pieces, one in San Fran and one aboard Gallaxhar’s ship). The monsters are fine – and I love their designs – but they suffer from Seven Dwarfism, where they exist only to support Susan. The inevitable comparison to Pixar arises here; while I think the animation stands up as well as anything coming from those guys, Monsters vs Aliens doesn’t have the depth of character work that Pixar films have. The monsters don’t have personal journeys, and while it’s cool to have a girl as the lead in a movie like this (something Pixar has been lagging with), the remaining monsters should have arcs of their own. There are moments where arcs are brushed against – The Missing Link is really fond of Insectasaurus, for example – but they’re heavily backgrounded.

And then there’s the bad. Stephen Colbert is simply rotten as The President, a character who feels like he walked in from a Shrek film – huge, broad and unfunny, every scene with this character (including a bizarre during the credits coda) made me grimace. Nearly as bad is Kiefer Sutherland’s General WR Monger (GET IT?!?), a goofy character who fits in with the Mad Magazine style of the film… but like from a really shitty issue of Mad Magazine.

While Monsters vs Aliens doesn’t suffer from the Shrek films’ suffocating winking reference making, the movie is chockful of shout outs that monster movie fans will enjoy. I dare any monster fan to not smile when Galaxhar shouts ‘Destroy all monsters!’ or to grin when B.O.B’s quickie origin scene has a shot homaging the Blob coming out of the movie theater doors. They’re great touches, and I like to imagine that they’ll lead kids to discover some of the wonderful monster movies of the past. I hate to think of a whole generation coming up with no actual experience with The Blob or The Creature.

I saw the film in 3D IMAX and have to say that the presentation is spectacular. There are a couple of ‘in your face’ 3D gags (including a paddle-ball gag that’s a riff on Vincent Price’s House of Wax – another great reference that only a few will get), but most of the 3D work is the subtle creation of depth. I imagine the movie will work just as well in 2D, but if 3D is available I can’t recommend it highly enough.

Monsters vs Aliens comes so close to being something truly special, but even as a movie that’s enjoyably above average it beats the pants off everything else that Dreamworks has done so far. The end of the film is – surprise! – open ended for a sequel, and I do hope one is in the cards. I’d like to see more monster mayhem and I’d also like to give the non-Susan monsters a chance to shine with their own stories.

One last thing: While Seth Rogen’s brainless B.O.B is the standout when it comes to voice work, the dialog-free Insectasaurus is the breakout character. If Monsters vs Aliens hits big, every kid in America is going to want a stuffed Insectasaurus that roars. The guy’s just adorable – which makes his absence on the poster simply weird.

7.5 out of 10 as a movie

8.5 out of 10 in IMAX 3D as an experience