Darkness-Induced Audience Apathy: Characters are slaughtered left and right. Anything the heroic characters in the series try to do ends in complete failure while the villains are borderline invincible. Even the Breather Episode late in the series that focuses on Edgar, Sabin, and Tifa retroactively is hit with this, due to Kain effortlessly using his control of Lenna's dragon to have it kill all of them almost immediately after. As a result, it can be hard for some people to care what happens considering that it soon becomes predictable that anytime someone tries to go up against Kain or his allies they'll automatically die.
One-Scene Wonder: Red XIII appears in only one episode, but his final moments in which he dies fighting for the side of good and refusing to compromise his morality are incredibly awesome.
Villain Sue: Kain's forces, arguably. They take out any heroes who attempt to oppose them with little to no difficulty whatsoever, sometimes even pushing their wins to ludicrously cheap levels. Especially evident at the end of "Showdown" where Edge is clearly winning his battle against Lionheart and is about to finish him off. One quick fade to black, and when the things clear up Lionheart is walking away from Edge's dead body, the latter having been stabbed.