Anvilicious: The effects of the wrong political party taking control end up turning America into a Death World within a few decades, to the point where the main character is eaten alive by dogs.
Harsher in Hindsight: One of the headlines on the Dakota Online Magazine feelie is Queen Di at 70. Princess Diana died in a car crash in 1997.
Just Here for Godzilla: The liberal politics of the game are overshadowed by the sci-fi elements of PRISM. Unless you go digging through menus, it's easy to play most of the game without knowing what the Plan for Renewed National Purpose involves. You can see its effects, as the police state gets worse and worse, but the plan behind it isn't as visible.
Paranoia Fuel: "You have spent twenty years living a normal, unsuspecting life. You are YOU. The suddenly, one day, the universe around you is torn away, and you learn that your whole life has been a charade, a carefully calculated scientific experiment. Perhaps, at this very moment, you are a normal human being, sitting in some comfortable armchair reading this story. But - perhaps you are not."
Tear Jerker: The short story prologue describes what are probably the most painful moments in Perry Sim's/PRISM's life.
Additionally, several events in the future simulations (especially regarding his son) are soul-crushingly depressing.