Conan for NES. The game is a monstrosity and is broken in every sense of the word. I'm still angry 20 years later for being pulled in by the awesome artwork and the promise of Conan-style skull crushing.
The graphics are horrible, even by NES standards. And what's sad about that, is that the game was released in 1991, the same year as the Super Nintendo, so it should have been a great looking game since the NES had showed us all it's tricks by then. The enemies spawn randomly, and when I say randomly, I mean anywhere on the screen is fair game, at any time. So you could be in the middle of jump, and and enemy will spawn in front of you, which happens pretty often actualyl, and when it happens you suddenly plummet straight downwards like a falling rock to a fiery death below. And the controls, stiff as a corpse.