
After the striking warmth and intelligence of The 40-Year-Old Virgin, Knocked Up is a real comedown; though it seems to have convinced the professional critics, it rarely rises above the level of a poorly-structured series of skits, with an inexplicable outcome. While some of the individual bits are extremely funny, and even, on occasion, perceptive, as a whole the film is far too episodic, and regularly grinds to a halt when Apatow attempts to switch gears and subplots (the fratboy episodes, in particular, outstay their welcome, both individually and collectively). The impetus behind this lack of overall shape isn't bad - Apatow has a wonderful group of performers, and likes to give them plenty of freedom - but the director is ultimately unwilling, or unable, to shape his material in truly satisfying ways, while some of the references are so thoroughly and deliberately 2007 that the film is likely to age awfully fast.
It's a rare comedy that justifies a two-hour running time, and this is not that film; the lack of a sharper editor is sorely missed, with scenes tending to peter out rather than coming to a satisfying conclusion, and while the birth sequence itself is very funny, there's an awful lot of work required to get that far. Hardest of all to swallow is the abrupt shift by Katherine Heigl's character, Alison, whose decision to remain with the slovenly and, to that point, often actively obnoxious Ben (Seth Rogen), is utterly unconvincing; it's a plot development that doesn't do right by Alison, who - unlike Catherine Keener's character in The 40-Year-Old Virgin - exists only to help Ben grow up (it's interesting that at the end, Ben gets to narrate the tale of the baby's conception while Alison is asleep, as if to underline the fact that she's not all that relevant to this tale).