LogFAQs > #976111840

Superman 64: Playing it on easy removes the rings from the ride stages, and it will en before the second to last action stage. Normal mode ends before the last stage.
The first X-Men (1993) game for the Sega Genesis ends halfway through on 'Amateur' Mode (the easiest difficulty level) with a closeup of Magneto's sneering face and the text, "Amateurs can never defeat me! Try being a hero!" scrolling by.
Contra 4 not only ends at stage 7 on Easy mode but outright taunts you, telling you that you'll never see the ending on Easy. With that exact wording!
Contra III: The Alien Wars will only let you fight the True Final Boss on the hardest setting. The Easy and Normal mode will stop after the Final Boss reveals it is Not Quite Dead and you get a message telling you to play on the next difficulty level.
Castle of Illusion ends after you collect the third gem if you play on easy, with Mizrabel merely giving Minnie back to you. It encourages you to try Normal mode with the promise of "many new and exciting levels".
Mighty Morphin' Power Rangers on the Sega CD will end on earlier levels when playing on lower difficulties. You can only play the entire game on hard mode.
Monkey Island 2: LeChuck's Revenge, Easy mode is "I've never played an adventure game before, I'm scared", and if you choose this mode, most of the puzzles are solved for you.
The Snes version of Bram Stoker's Dracula features this, if you beat it on Easy mode the game ends with Harker allowing Dracula to escape. Only on Normal or Hard mode will you be able to continue past the 3rd or 4th stage.
Cyborg Justice on Genesis. Players can experience the Arcade mode through 5 difficulties; however, "Relaxed" and "Easy" end the playthrough prematurely - at Level 3-3 and 4-3 respectively. Getting to the end is possible on "Normal" mode and above.
Double Dragon II: The Revenge for the NES gives it to you on this one in the American version. Playing the game on the "Practice" setting only takes you to the third stage, while "Warrior" takes you through the whole game except for the final stage. Fighting the True Final Boss to see the ending can only be achieved by playing the game on "Supreme Master", the hardest of the difficulty settings.
The Game Boy version of Double Dragon II ends after the first four (of ten) stages when played on the Easy setting.