We're all used to heroes winning out over the bad guys. The bad guys get theirs, justice is done, and the heroes walk away happy. Sometimes things are a little more bittersweet, but we at least expect the villain to lose in the end. One can even get away with a Downer Ending where it ends badly for the heroes, but many of these kinds of endings are "nobody wins" affairs where everybody pays the price (fatally or not). Even if the villain wins in these kinds of endings, it's usually at great enough personal cost to the villain that he or she is utterly ruined as a result.