7. Batman - Batman NES
Clearly coded by someone who hadn't read the liner notes on Batman, the original Batman game on NES deviates quite substantially from its movie counterpart.
Where in the movie, Batman uses his grapple gun to attach Joker to a nearby gargoyle statue - thereby inadvertently killing him, as Joker loses grip on his escape helicopter and plummets to his death - in the game it's a completely different story.
Here, Batman straight-up grabs the Clown Prince by his neck collar, states that he "knows you murdered my parents", repeats Joker's line about "dancing with the devil in the pale moonlight", and throws him straight off the top of the clocktower.
We see Joker fall all the way down, only for the game to - again, mimicking the movie - zoom in on Joker's face, showing he died smiling.
Still, this is a major deviation for the character of Batman, and as the sequel would resurrect Joker with no explanation and literal seconds of "cutscenes" just showing he's alive and well, the Dark Knight's Nintendo debut remains the only Batman game in history where the character actively kills.