As the closing credits to St. Vincent roll, Bill Murray's character, the titular Vincent MacKenna, hums the words to Bob Dylan's "Shelter From the Storm" as he attempts to water his dirt patch of a lawn. The actual song -- one of Dylan's very best -- plays in the background. Murray is listening to it on a battered Walkman, and he's singing poorly, eliciting memories of some of his beloved roles -- a little bit of Carl Spackler here, a bit of Don Johnston or Steve Zissou or Bob Harris there.

I was glued to my chair of course. I almost never stay for the closing credits, Marvel Studios films excepted, yet there I was compulsively watching Bill Murray because, well, it's frickin' Bill Murray. If I'll watch him sing a lousy Dylan cover while he turns dust in to mud -- just add water! -- then what won't I watch him do?

That's probably an overly ominous way to frame this review, but it is also the most interesting single thing about St. Vincent. That is to say that first-time writer-director Theodore Melfi, who pulled off a sizable coup just by getting the notoriously, um, flaky Murray to agree to star in his film, managed to get transformative mileage out of Murray's charms.

St. Vincent is not a terrible film, but neither is it tremendous. Murray's turn as a gruff, grizzled, chronically misbehaving Vietnam War veteran who reluctantly befriends his neighbor's young son Oliver (Jaeden Lieberher) is its clear highlight. A drinking, womanizing, disheveled Murray explaining what a Trifecta wager is to a bright-eyed, smart kid at Belmont Park is just one example of the fertile comedic ground to be tilled, and much of that ground is covered by the end.

But Melfi builds in a sensitive side to the character as well. Vincent pushes most people away, but the few beings he allows near — an absurd-looking Persian cat, a pregnant Russian prostitute named Daka (Naomi Watts), his dementia-stricken wife, and, yes, eventually Oliver — are routinely on the receiving end of his incredible kindness, whether it’s an ultrasound so Daka can discover the gender of her child, the laundry he does every week for his wife, or the self-defense lessons he provides to his pseudo-protege.

Many of the other characters possess similar strengths and frailties. Oliver’s mother, played by Melissa McCarthy, is scraping by following a painful divorce, just barely managing to send her son to private school through long hours as a CAT scan tech. Daka is struggling with the implications of her pregnancy and her profession, one which is diametrically opposed to responsibility.

They are drawn with great familiarity (the so-and-so with a heart of gold), but they are easy to root for. Melfi is overly sentimental and he is not subtle. But where he really runs in to trouble is in packing this story with a bunch of largely unneeded vignettes. Terrence Howard shows up as a loan shark who mostly just tells Vincent what a deadbeat he is, which is wholly unnecessary when you consider the squalor in which he lives, the drinking in which he partakes, and so on. Chris O’Dowd, playing a teacher at the Catholic school Oliver attends, gives Melfi the excuse he needs to bring Oliver and Vincent together for the token feel-good ending. The story keeps moving, but not always with much purpose, and so it drags for long stretches.

Yet Melfi still has Bill Murray, and that is enough to give St. Vincent verve and energy for other long stretches. Is this cheating on Melfi’s part? I’m afraid to answer the question. Without Murray, I am certain that this film would be an unwatchable mess. With him, it’s a … watchable mess, I guess? Perhaps those distinct closing credits are an unintentional admission of just that fact.