Partly this is a function of seasonal multiplex expectations (and their attendant marketing). From a distance, "Tammy" looks for all the world like a big, brash comedy. But seen close-up, it more often evinces a low-key indie, with deep reservoirs of melancholy at best and wan clichés at worst. McCarthy plays the titular born loser, who loses her car, fast-food job and philandering husband in rapid succession. Walking home to Mom (Allison Janney) a few doors down, Tammy announces she needs to be anywhere but here and reluctantly accepts her hard-drinking grandma Pearl (Susan Sarandon) as her partner in crime (at one point, literally) since it's Pearl who has a car and cash in the thousands.
The lazy road-movie formula that immediately kicks in might not have been an obstacle to fun had McCarthy and Falcone been in a quirkier mood. But "Tammy" proves unfortunately unfunny most of the time, and dispiritedly "been there, done that" as the bickering Tammy and Pearl pick up a father-son pair — one horny, one sweet — at a roadhouse (like everything else in the movie, Gary Cole and Mark Duplass seem uninspired). The ostensible end of the line is Niagara Falls, a liberation destination to baptize the heroes for their new life, lessons duly learned.
McCarthy delivers another all-in performance, but so much so as to be more sad than funny much of the time. This may be no object for her true, mad, deep fans, but the average viewer will expect the raucous comedy "Tammy" has only in short supply (the film's comic highlight being a passage involving passive-aggressive apparent armed robbery). The utterly reliable Sarandon hits no false notes, but the material lets her down, which can also be said for Kathy Bates as the fix-it-minded co-host (with Sandra Oh) of a lesbian Fourth of July party.
Though nothing much lands here in terms of comedy, "Tammy" attempts to compensate with themes of familial reconciliation (however arbitrary in the choice of grandma over mom or hubby) and redefinition of self. But you can almost feel the movie sheepishly shrugging sorry when the credits play it off with a couple of tag scenes and a McCarthy outtake. We still love you, Melissa. Better luck next time.
Rated R for language including sexual references. One hour, 36 minutes.
— Peter Canavese