Love them or hate them, factory-made Hollywood romantic comedies are a staple of cinema: the faces may change but the same formula exists. It's these films that writer-director David Wain pokes fun at in lively comedy They Came Together, in a similar vein to 80s classics Airplane! and The Naked Gun.

Wain's debut feature was 2001's Wet Hot American Summer, in which he similarly parodied summer-camp movies. Since then he has produced a mixed bag of offerings - the terrific Role Models (2008) was followed by the laclustre Wanderlust (2012).

They Came Together, which featured at Greenwich's Sundance Film Festival in April, is itself a mixed bag. For every joke that lands there's one that misses - it's saving grace being there's a lot of them, so enough laughs to make it worth watching.

The film starts with a seemingly happy, well-adjusted New York couple, Joel (Paul Rudd, Anchorman) and Molly (Amy Poehler, Parks and Recreation), recounting the story of their relationship to another couple over dinner. A flashback narrative commences, in which everything you've ever seen in a romantic comedy happens.

There's the first meeting in which they hate each other (Joel works for a huge corporate candy firm that threatens Molly's small, quirky, independent candy shop - a plot line brazenly lifted from You've Got Mail), the bonding over shared interests (they both like 'fiction books'), the cutesy montages (played out to alternative rock), the break-up, wedding day jitters and altar-dashes - with the humour varying from well observed comedy to dumb puns (a literal gag about a waiter with 'pole up his ass' stands out).

Wain has assembled an impressive supporting cast plucked from the cream of American sitcoms - Cobie Smulders (How I Met Your Mother), Max Greenfield (New Girl), Ed Helms (The Office) and Jack McBrayer (30 Rock) all appear - but these parts are too underwritten to leave a lasting impression.

It is the ever-reliable Rudd and Poehler who are crucial to the film working, and they hold it together with their trademark wit and charm - the funniest moments in the film are when they share the screen (a coffee shop scene during the 'getting to know you' phase is seamless).

The concern with They Came Together is, even with a brief running time of 83 minutes, it wears thin, often feeling like little more than sketch comedy. However there are laughs to be had here - and that, after all, is what comedy is all about.

RATING: THREE OUT OF FIVE STARS

They Came Together is out in the UK later this year. BBFC rating: 15.