50/50

50/50 isn't the first cancer comedy; Judd Apatow's Funny People took a whack at it only two years ago, with Seth Rogen riding shotgun there, too. But Funny People is really more a dissertation on a professional comic's damaged psyche, whereas 50/50 genuinely wants to explore what it's like for someone – specifically, someone quite young – to undergo the unimaginable awfulness of a cancer diagnosis.

Writer Will Reiser based the script on his own bout with spinal cancer in his early 20s. His real-life best friend, Rogen, plays his own fictional surrogate in the film, looking and sounding exactly like the Rogen we've come to know and – a lot of us, at least – love in Apatow films: kinda schlubby, emotionally stunted, and a fount of dick jokes. It's good to have him back. Joseph Gordon-Levitt plays Reiser's stand-in, a Seattle-based National Public Radio producer diagnosed with a rare kind of cancer that comes with not great odds (the title's 50/50).

Gordon-Levitt is an actor who radiates decency – which sounds like the equivalent of a "really good personality," I know, but it's actually a pretty neat trick to pull off. He has dynamite charisma with Rogen and Anna Kendrick (Up in the the Air), who plays his therapist, Katherine, with a just-right swirl of tenderness and pep. And, in keeping with a character who is decent, kind, and maybe too cautious, Gordon-Levitt skips big theatrics for tiny masterstrokes of emotion: a cock of the head when he sees Katherine for the first time as a woman, not a postdoctorate mouthpiece for bullshit healing exercises; an escaped wail for his mother as he goes into surgery; and so much winning matter-of-factness in his delivery of Reiser's cuttingly funny writing ("Nobody wants to fuck me; I look like Voldemort.").

Line to line, 50/50 dispatches the comedic and the dramatic with aplomb. Yet, overall, there's some flabbiness (a girlfriend subplot that sputters on for too long, an aside about a volcano that feels like a mind's-eye metaphor that never quite caught on the page). But mostly it's just terribly funny and sad and beautifully acted and terrifically feel-good for being, you know, a cancer comedy.