Before I Wake is a short psychology SF story. Those are tough to write, since what goes on in someone else's head is pretty much speculation anyway. So Robinson adds a physical explanation for the events. Ever awakened from a dream that you were dreaming? This creepy sensation has inspired a lot of fiction, and here it gets a hard SF twist by being generated by a radiation field. Everyone is continuously dreaming and waking at the same time. Makes it tough to stay alive, and pretty much no one is. Our protagonist fights it as best he can, but given glimpses of reality after dreaming, it's just too much.
Short stories often end up sort of hopeless like this. It feels like a story that's much older than 1990--after all, the Internet existed by then, if not the WWW. But it's fun to see someone basically pull off a psychological SF story that's not about drugs. 3 stars for trying.