Writer/director Mike Birbiglia clearly loves the purity of improvisational comedy, and he makes it the mission of his film to explain that love to the masses.
The momentum for “Don’t Think Twice” is provided by its wonderful comedy cast, including Keegan-Michael Key and Gillian Jacobs as Jack and Samantha, a New York couple who are opposite on the ambition spectrum.
Knowing there’s a producer for “Weekend Live” in the audience for one of their small club shows (Birbiglia does even try to hide that it’s a “Saturday Night Live” clone), Jack showboats — a cardinal sin in improv.
The twists and turns in their personal lives often feel inauthentic — like script devices to propel the action.
Like Tom Hanks in “Punchline,” Key is a beloved actor who explores a darker version of himself, allowing for some interesting nuances.
The result seems to be a huge asset during the improv scenes, which charge the movie with the authenticity that it often lacks off the stage.
Birbiglia’s writing also captures the gallow’s humor, insecurities, paranoia and bonding between struggling comics.
Not everyone in “Don’t Think Twice” follows the unwritten comedy rules, but the filmmakers are a credit to the improv code.