Tim Minchin doesn’t follow the rules. The comedic songwriter first shook things up on Broadway with his score for Matilda The Musical, a darker take on the Roald Dahl children’s book than many had expected. His daring paid off with a 2013 Tony Award nomination.

He returns to Broadway this spring with Groundhog Day, currently onstage at the August Wilson Theatre. It was that same potential for darkness that tempted him to musicalize the movie about TV weatherman Phil Connors (Andy Karl) stuck reliving the title holiday in Punxsutawney, Pennsylvania, over and over again. Fans of the film, which stars Bill Murray as Connors, needn’t worry. “The movie is so successful because of the balance between romantic comedy and existential crisis,” says Minchin, “and we didn’t want to f—k that up.” Before he could preserve that balance, though, he needed to find his way in musically; it was through his Act 2 opener that Minchin found it.

“Playing Nancy” is a mournful ballad sung by a secondary character as she contemplates her lot in life as “a brief diversion, just the detour on the journey of some man.” In that lyric, Minchin subtly declares his concept for the show.

“[Phil] goes through these musical phases as if he’s going through maturation as a human being,” Minchin says. “The styles of music are meant to parallel his stages [of life] from solipsism through hedonism into self-loathing, and he learns all these lessons and eventually finds what we now call ‘mindfulness.’”

In fact, Minchin’s score is a jigsaw puzzle of musical genres. In addition to the phases and changing sounds of Phil, the ensemble sings in styles of polka, samba, jazz—there’s even a brassy tap number and a funk mix. Despite the different styles, Minchin unifies the score on a sonic level, restricting himself to specific chords and harmonic structures.

If his melodic approach sounds complex, it’s only due to the fact that, for Minchin, sound is inextricably linked to lyrics—and Minchin is a wordsmith. “I’m incredibly didactic and lyric heavy,” he says. “It sounds so pretentious, but once you’ve really got into Shakespeare, you really don’t ever want to treat words like, ‘Oh that’ll do.’

“My job is to go, ‘No, no, you’ve got to listen to every word, and once you make that contract with [the audience], you better uphold your end of the bargain. You better always be doing something.”