Super Fire Pro Wrestling Special had one of the worst video game endings ever, in my opinion. Super Fire is a professional wrestling game, where you were required to constantly fight others, win matches, and move up the ranks. When you had reached the top, you got the chance to fight the champion for his title. If you had beaten him, you would be declared the new champion. You eventually defeat him throughout the game's ending, but the game doesn't actually send you home with a feel-good moment. At the end of the game, you go back to your home and start thinking about all the mistakes that you've made in the past. All of this causes you to start losing your mind. Eventually, you take out your gun from your drawer and shoot yourself to the head—committing suicide. After that, the game fades to black.
Star Wars: Knights of the Old Republic 2 also had a bad ending. The game itself was pretty good. Its story was extremely well-written, and made you feel that you were actually a part of the game. You flew all over the galaxy, met new people, made allies, fought enemies, and did all sorts of missions. But the ending, though—it was just... blegh. D: The game ended with a side-character (and not a main one) making constant dialogues, which were incredibly boring to sit through. These dialogues weren't very important, either. They were quite trivial.