Milly Alcock’s spirited performance makes this Superman spin-off just about tolerable. But it lacks a single fresh idea

"Supergirl," starring Milly Alcock in the title role, is getting mixed reviews from Rotten Tomatoes critics.

A punk-rock Supergirl is a welcome, jagged riff on more buttoned-up superheroes, and Milly Alcock is terrific in the role.