It's hard to adapt a movie to the world of video games. Diehard fans want an experience that accurately represents the source material, but the first level of Super Mario Bros. has a bigger body count than all of Die Hard. Usually game developers get around this problem with a weird boss fight here or an unusual story deviation there, but apparently they sometimes leave their early draft of the script in the wash, and can only loosely guess at the ending based on the shapes of the inkblots.
5Indiana Jones' Greatest Adventures -- The Wrong Grail Makes You a Supervillain
Indiana Jones' Greatest Adventures is a Super Nintendo platformer that takes players through iconic scenes in all three movies (it was a simpler, less Crystal Skull-filled time). But then you reach the end of The Last Crusade, the one about the search for the Holy Grail, which will keep anyone who drinks from it alive. Unfortunately, it's hidden in a secret room full of fake grails that will keep you dead forever, and also Nazis are after it. In the movie, Nazi henchman Donovan chooses incorrectly and withers away into dust. But in the game ...
How the Game Missed the Point
Wait, what? He gets so scared that he spontaneously loses all his flesh? And instead of having the good grace to die of old age, Donovan goes on living as a sentient skeleton. He deserves major credit for how quickly he adjusts to what one would assume to be an awkward and painful transition, as he immediately begins leaping about with the range of an Olympic gymnast and uses his own skull as a lethal bowling ball against Indy.
Thus outing himself as Janeane Garofolo's father once and for all.
When you defeat him, he continues to defy logic by bursting into flames, despite being made entirely of bones and the fact that you've only been whipping him, not dousing him with gasoline.
This is why you always employ a safety word during S&M sessions.
From the Nazis' standpoint, they'd probably prefer to get their hands on more fake grails instead of the real one. Sure, immortality is great for the Fuhrer and his dog, but turning all of your foot soldiers into an army of intimidating skeleton monsters is going to be more useful in wartime. One bitchin' grail kegger later, and boom: The Allies are trying to beach in Normandy under a blitzkrieg of magical skull attacks.
"The only thing we have to fear is ... this, actually. Shit."
4Teenage Mutant Ninja Turtles -- Splinter Randomly Gets Better
Asking someone which Ninja Turtle is their favorite is like asking which deity is their favorite. But let's not forget Splinter, the wise teacher who instructed the turtles with all the dignity and grace that a stock character resembling a diseased Muppet can muster. Splinter's origin story varies, but the most well-known version is that he was a Japanese martial arts expert forced into exile by Shredder. He lived as a sewer hermit in New York City until he and his pet turtles were exposed to barrels of an oozing green mutagen, because hey, that's what you get for living in a New York sewer.
How the Game Missed the Point
The first TMNT game for the NES didn't have much of a story -- Shredder kidnapped April O' Neil, because that's what bad guys do, and you had to save her, which is what good guys do. Just choose a turtle and painstakingly fight your way through some of the most maliciously designed, death trap-filled, all-around bullshit levels you've ever seen in a video game. Good luck!
The little-known Tenth Circle of Hell.
The game was balls-to-the-wall impossible and hated children more than most clowns, so what did you get if you managed the Herculean feat of beating it? This:
"Hey, I bought you a beer."
"I also saved the universe from unspeakable evil."
Uh ... why exactly are you allowed to become human again? Did the Shredder in this version curse you like a miffed gypsy? Nope: Splinter still had his DNA mutated by ooze. But apparently you can undo genetic damage just by being super relieved. Also, why aren't the turtles affected? They're mutants for the exact same reason that he is. April, meanwhile, seems rather unfazed by the whole "miraculous recovery" thing, which is rather odd, considering that she's a frigging journalist.
"Pizza Hut's low, low prices are the real miracle worth investigating!"
To be fair, three panels of text with images is more of an ending than most NES games got -- many barely managed a "thank you." That actually makes this more impressive: They managed to screw up the entire mythos in only three measly panels. It took Lucas three whole movies to manage that.