The trailer doesn't do it justice. I can't promise you'll like the movie at all but, especially if you're a child of the 1980's, this film should speak to you. It's not a groundbreaking or subversive genre breaker but it's a simple story told well with surprisingly good music.
I only saw it because so many folks were recommending it. In fact think it was a Screen Junkies podcast where they were calling out their picks of their favorite films of 2016 (I was hoping to hear Capt. America: Civil War at the top) and was surprised when two guys brought up Sing Street with one guy ranking it at the top of his list. The title is uninspiring and the trailer is 'meh,' I agree.
Speaking of miscalculated trailers the worst trailers IMO were for Fight Club. They sold the film as just a basic, unoriginal action movie and I didnt see it in theaters. But, with the DVD release, I remember hearing a really interesting radio interview with Edward Norton about Fight Club. So I got it on DVD and was blown away. And I was surprised at how even many professional film critics misread the film entirely.
