I never got around to this in my De Palma retrospective, so when Spectrum Culture decided to do one of its own, I knew I had to cover it. The results are...middling, like so many early De Palma efforts, though as a concentrated experiment in sustained split-screen usage it remains an intriguing work. De Palma's highly cinematic techniques ironically enhance the theatricality of the filmed performance, though soon he would be employing the methods for even more lavishly stylized effect. Nothing more than a curio, perhaps, but De Palma has made far worse.
My full review is up now at Spectrum Culture.