The Buddy Schism: 9/11 drives a wedge between college pals in Reign Over Me.

Reign Over Me revolves around 9/11, but it’s likely the film will be known as Adam Sandler’s second attempt to go serious. Not Spanglish– or Click-serious—think more along the lines of Punch-Drunk Love. Writer-director Mike Binder certainly did, as here Sandler’s character is similar to the one he played in Paul Thomas Anderson’s 2002 movie. In a lighter moment Sandler might have put it this way: “I’m Isolated Crazy Man. Give me some candy!”

Charlie (Sandler) isn’t the easiest person to reach out to, but his old college roommate, Alan (Don Cheadle), tries to anyway after they run into each other one day in New York. Charlie lost his wife and kids in the 9/11 attacks and has since shut down: Years later, he hasn’t gone back to work as a dentist, keeps dust covers over the furniture from his former life, and spends most of his time playing music and video games. He accepts Alan’s friendship but soon gets selfish with it, acting like a child as he teases his married friend into going out every night and not coming home until way later than he wants to. When Charlie starts taking the “fun” out of dysfunctional—he blows up at times, especially when Alan asks questions about his family—Alan, who’s also a dentist, is initially put off, but Charlie’s instability ultimately makes him want to help even more. Alan’s wife (Jada Pinkett Smith) isn’t exactly thrilled with the situation.

It’s true that Charlie is a very ill man. But viewers may sympathize more with the circumstances than the person. Binder gives Sandler free reign to go into full-on eccentric mode with ratty hair, twitchy mannerisms, and an infantile, mouth-full-of-peanuts delivery that’s irritating as hell. Some comedic scenes make Charlie seem lucid and likable, but more often he’s stubbornly uncommunicative and impossible for anyone but a mental-health professional to deal with. Quite frankly, no matter how sick you know a character is supposed to be, it’s difficult to watch a regressing jerk (especially at a bloated two-plus hours). A pushover like Alan isn’t fun company, either, though Cheadle brings his usual energetic charisma to the role of someone who tells his wife he couldn’t come home last night because he was “stuck in Charlie world.”

But once Charlie begins to open up—both to Alan and to a therapist (Liv Tyler)—Reign Over Me improves remarkably. (The title comes from the Who’s “Love, Reign O’er Me,” which is what Charlie listens to on giant headphones when he wants to shut out the world.) Eventually there is a glint in Sandler’s puppyish brown eyes that makes his character seem playful and, finally, compelling. The script at last succeeds in wrenching sympathy out of you: Charlie’s description of what happened that day will take you right back to it, and after he’s arrested for assault, a brutal hearing in which an attorney brings pictures of Charlie’s family shows that maybe Charlie’s reaction to the tragedy isn’t so extreme.

When Binder makes the story about Alan’s transformation, too, the film derails again: Suddenly, he’s a closed-off husband and realizes he “doesn’t want to be that guy.” There’s also a rather unbelievable happy ending to Charlie’s tale. But Reign Over Me’s winning moments are nearly enough to make you forgive its flaws—by the final scenes your gut has already been successfully punched.