Most difficult game you played

[Jolt]

Another World:



Notice how the guy finishes the game in 20 minutes.
That's because not only does he already know exactly what he must do, he also has quite a bit of luck and skill during the firefights.

I probably died hundreds of times before I finished the game. Since the game is by checkpoints, it was highly annoying dieing dozens of times and going back to the same checkpoint. Plus the fact that the levels were highly confusing, and if you didn't do exactly the correct path, you'd die, made it for an highly difficult game. Fortunately, I managed to finish the game. And even the ending is quite disapointing, taking into account the effort that you need to put, to finish the game.

EDIT: More up to the point.