Us’ greatest weakness is that it is both full of huge, complex ideas worthy of analysis, but also a plot that falls apart if you think about them too much. The class allegory that posits that the privileged few never gives a second thought to those linked to them — by virtue of their humanity if nothing else — until they’re being physically threatened is one that is worth careful consideration. But aside from Red, who communicates with Adelaide in a wheezy flap of a voice only rarely used, these doppelgängers feel more like zombies than our worst selves reflected back, and the big finale relies on a wordy information dump that’s more telling than showing. It’s messy, and a little clunky, but more than that, having loose ends tied up so neatly cheapens the message. Things are scarier when they aren’t explained.