A post-apocalyptic parody? Brooker is a media satirist, so I want to give him the benefit of the doubt about this episode. My 6 rating is because even as dry satire, it's underwhelming.
The premise is: mechanical dogs have decimated life in Scotland and presumably the world. The episode is essentially a prolonged chase. Instead of zombies in 28 Days Later, we've got robot dogs.
There aren't many beats. Maxine Peake runs, trembles, inhales, sobs, etc. Ms Peake isn't given a lot to work with, yet does an admirable job. If she appears to over-act: what else is she supposed to do?
So why is it possible parody? The first clue is it's in black & white. It looks a lot like Besson's wonderful The Last Battle. I'm tempted to believe that Brooker is giving a nudge to Besson to ask how he went from crafting quiet, beautiful films to his current excessive style. My second clue is the final shot. With the overwrought music, saccharine morality and the God-like perspective ... well, I hope Brooker understands what that means to the viewer.
As a sincere story, it's silly. As a parody, it's not skewering much. This one's a swing and a miss. But I'm optimistic that Brooker has many more interesting stories to tell.