[General Discussion] Hardest game(s) you've ever played

Ninja Gaiden 3 for the NES. NG1 was tough, but I stuck with it and somehow made it through. NG2 was easier thanks to the shadow clones and is by far my favorite of the trilogy, but 3...goddamn 3 was just insane. Instead of Shadow Clones, your main weapon powerup is a longer slash with your sword. I think the furthest I made it to 3 was either the end of the 2nd level or the beginning of the 3rd level, but after losing all of my lives I started using save-states over and over until I finally beat the game.

Also, for those of you saying TMNT1...I had a players guide video that helped me out back in those days (tips for beating TMNT, Metal Gear, Skate or Die, and Defender of the Crown), so I didn't suffer as much as you guys. However, this game is a piece of cake to me now and I can pretty much beat it every time by using one or no continues. I can't say I can beat it without losing a turtle, I somehow manage to make a mistake around the fourth level with the damn fiery pit in stage 14 or 15.

Jam it back in, in the dark.