1. TMNT - NES. Who gets to the end in that game?
I agree that the last level is terribly frustrating. Those damn flying guards... man!
2. Ghosts n' Goblins - NES. Who gets to the third level in that game?
Beat it, sorta. It took me about two hours (as well as almost eighteen years of practice) to get through those six whole levels. Then you get the dreaded "Room of Illusion" and you have to go through the frickin' game again. -_-
3. Ninja Gaiden 2 - NES.
Beat it, you should replace it with Ninja Gaiden, which I also beat. Ninja Gaiden II's easier than Ninja Gaiden.
4. Metal Gear - NES.
Didn't play much. I like the MSX version better anyway. Also,
^ That li'l code right there's what caused Nintendo to start removing vowels in their passwords.
5. Out of this World - SNES
*Genesis' version's death music plays*
6. Super Mario Bros. The Lost Levels - NES.
People who think this game's difficult obviously hasn't played enough games in their life.
Some examples of ridiculously hard games would include:
Adventures of Lolo 3 - For people with an above average intelligence ONLY!
Contra III: The Alien Wars (Hard Mode.) - The US version requires you to beat it on Hard to get to the actual ending. Good luck! I eventually made it, though, and it's well worth it when the game calls you a "Video champion."
Conan: The Mysteries of Time - Not only do you need patience, but you also have to have the sanity to play through this crapola. Do yourself a favor: Don't play it.
Darius Twin - No continues, no extra lives, 'nuff said. On the bright side, you get to keep the powerups you get.
Life Force/Salamander (NES) - The only game that actually made me use the Konami Kode. That's saying something.
Shinobi (PS2) - I can't imagine going through the game on harder difficulties.
Shining Force Neo - Prepare to hear Max shout "No way!" a lot as you trudge through this game before seeing the Game Over sceen for the 180th or so time.