"Don't Think Twice" is rated R, though it's kind of hard to see why – not that it would interest teens anyway, being a story about adult crises. It has one F-word that I recall, as well as a few uses of God's or Jesus' names in vain; if anything slipped past me, that is a reflection of how low-key any foul language is here.
One surprising pro-life subplot involves the girlfriend of a main character, who discovers she's pregnant from a previous fling. She says that being in her 30s, she can't consider not having the child, and her new boyfriend in the improv troupe steps up and offers to change his entire life and become responsible by offering to take a real chance on their relationship and serve as the child's father as well, with strong implications that they're heading for marriage.
There is a scene in which an unmarried couple is having sex but are hidden from their bare shoulders down by sheets, and another scene implies that Miles has just had sex with a young 20-something improve student of his. There are also a few moments in which marijuana is smoked by some members of the group, but is almost too casual to be noticed.
This is the second feature film that Birbiglia has written and directed, following his 2012 debut "Sleepwalk With Me." A veteran standup comic who took the "Sleepwalk" concept – the story of how he overcame a bizarre battle with sleepwalking to reach success - to a lengthy off-Broadway run in addition to national tours and a bestselling book, Birbiglia proved that he had real chops coming out of the gate.
By expanding his vision to an ensemble-based, character-driven film, he proves here that "Sleepwalk" was no fluke and he could very well develop into a filmmaker capable of keeping Woody Allen's style of comedy alive and well at the cinema. This is playing in a few major cities now, but is well worth seeking out as it expands into more cities and in its DVD and VOD runs.