In the years since Good Will Hunting, during which time both Ben Affleck and Matt Damon exploded onto the scene, a clear arc has begun to emerge for those two actors. It seemed, for a time, as if Ben Affleck was the real find: good-looking, affable, able to act tough in an action film.

But as time went on, Affleck got mired in lame romantic comedies, off-the-shelf action films, and whatever Gigli was. Damon, meanwhile, fell into the right crowd with George Clooney and Brad Pitt, and began taking more adventurous roles. As did Ben's brother, Casey, who would eventually take the starring role in Ben Affleck's much-liked debut directorial feature, Gone Baby Gone.

I found Gone Baby Gone to be a mostly good but, at times, amateurish film, and this trend continues with Affleck's mild sophomore slump, The Town. The difference this time? Ben Affleck has decided to take the starring role. It's this decision, I believe, that prevents The Town from living up to its potential. Despite being good in the role, Ben just got in his own way.

Charlestown, Mass., we learn, is the world capitol of bank robbers. A blue-collar New England town, Charlestown is rife with men who fall, generation after generation, into the family business. It's here where we meet Doug (Affleck) and his team of thieves. They are preparing to take a bank, adorning themselves with hideous ghoul masks and automatic weapons.

The robbery is mostly a success, but when the hotheaded James (Jeremy Renner, exuding the same intensity he displayed in The Hurt Locker) thinks that a clerk might have seen too much, he throws her in the van, blindfolds her, takes her ID, and dumps her by the water.

After the robbery, Doug drops by Claire the clerk's (Rebecca Hall) neighborhood to check in and make sure that she won't talk to the FBI. Without letting on who he is, he talks her up in a Laundromat, finds himself drawn to her, and asks her out on a date.

Meanwhile, FBI Agent Frawley (Jon Hamm, stealing every scene he's in) is tirelessly searching for Doug and his gang, his actions becoming more and more extreme as the stakes get raised.

It's here, as well as with James, that Ben Affleck makes a common mistake: the secondary characters are far more interesting and well-drawn than the main character and his love interest. Doug is basically a goodhearted guy who wants to get out of the business, who says things like "This is my last job" and "One of these days I'm going to leave this town and never look back."

But Agent Frawley and crazy James are more fascinating. A fiercely loyal thug from the poor part of Massachusetts, James went to prison for 9 years out of a sense of honor. He's an unstoppable force, knowing only how to crash through a situation, leaving whoever necessary in his wake. Frawley is equally bloody-minded, willing to do whatever and hurt whoever it takes to get his man. He's not a bad guy, but he ain't really good. Listen to the disdain in his voice when he mocks the poor Charlestown accents.

There are a number of thrilling set pieces in The Town, and some shocking violence, as well as some coy humor in the style of how The Departed occasionally dipped into comedy. It's nervous laughter, because you never know when the second shoe will drop.

Ultimately, The Town is a surprisingly slight movie. The romance between Doug and Claire is distracting and unbelievable, though it sometimes results in a legitimately tender moment.

Rebecca Hall is a magnetic presence, an unusual beauty who kind of epitomizes the girl-next-door cliché. Blake Lively comes out of nowhere in the third act in a devastating role as Doug's ex-girlfriend, and Chris Cooper has an equally effective cameo. Ben Affleck wisely gives the greatest speeches to Jon Hamm, who nails them with an ease and efficiency that serves as a great reminder (as if Mad Men wasn't enough) of his movie star potential.

But, to my chagrin, I left the theater thinking, "Well, hey, that was alright." This is a film of great parts that add up to less than its sum. - Three stars