Game: The Darkness.
Movie: Source Code. Now, this wasn't just a case of a movie with a bad ending. No, this went beyond that, to a movie with a perfectly good ending . . . and then they keep going.
Book: Stephen King's Thinner. That sort of ending would have worked way better in a short story, but
Now, I know, obviously, that they couldn't have had Jackie fight the Darkness and be free of it, it would have ruined the opportunity to make a franchise, but did they have to spend so much of the plot pretending that they were going to let him fight it in the first place? It just felt like a big climactic moment on the horizon, and then . . . oh, we're done.
Movie: Source Code. Now, this wasn't just a case of a movie with a bad ending. No, this went beyond that, to a movie with a perfectly good ending . . . and then they keep going.
So, the hero, who is essentially dead, but with his mind inside a program that lets him relive the last 8 minutes of another man's life, manages to discover the identity of a bomber (the objective of his mission), but begs to be sent back into the program so he can stop the bomber and save the girl he has fallen in love with, despite the warnings that none of it is real, and it's futile anyway. Nevertheless, he stops the bomber, saves the girl, and there are some touching romantic scenes with them together, while the audience waits for the hero to die, finally at peace. The woman he convinced to send him back into the program terminates his life, against the will of her superiors. This was, I thought, the ending, and it certainly did the job. I was quite touched by his determination to save this girl, even though it was futile. But no. Instead, it turns out that he actually changed history and creates a parallel universe, where the bomb never went off, and somehow the hero's consciousness is still inside the man he was inhabiting as well as in his own body, and his sacrifice was no longer a sacrifice at all . . . and meh. I guess some people might prefer the real ending, but I still think a good chunk of that film could have been sliced off at the end.
Book: Stephen King's Thinner. That sort of ending would have worked way better in a short story, but
you just don't have the protagonist fail drastically at his mission and stay cursed anyway after you've sent me through an entire bloody novel. A short story, that's fine, we don't mind if the main characters fail or die, but don't ask me to put emotional investment in this guy only to have him fail anyway.