There are knock-offs of “Mamma Mia,” and then there’s “Walking on Sunshine,” a British jukebox musical that sets out to replicate the sun-and-song formula to fuel another blockbuster success. Directors Max Giwa and Dania Pasquini aren’t fooling around here, actively looking to reheat “Mamma Mia” for a slightly younger audience, eschewing ABBA hits to mine the depths of pop music from the 1980s, creating a mix tape-style experience that merges singing, dancing, and easily digestible conflicts, while the whole thing is drenched in sun and colored with tanned skin. The laziness of the effort is remarkable to watch at times, even when its cast works diligently to put on a big show, making “Walking on Sunshine” amiable but frequently insufferable. Read the rest at Blu-ray.com