Props to mentioning Hitchiker's Guide to the Galaxy and ADoM. I have to add two games a bit along the same lines, or whatever. Anyway.
Nethack. I don't think anybody can call themselves a true gamer unless they have played Nethack. You don't have to beat it, 'cause it's just ridiculously difficult to do that. Just play it. And yes, I honestly can't understand what's up with the controls, who the hell decided which button does what, especially considering moving around, but anyway. To quote a great late man, you have to play Nethack "'cause it's a mother."
Another stupidly hard game was Moria, and here's a little story of it. I was playing with a Hobbit mage (or whatever the class is called). He was getting to be a badass mage, and could lay waste to all the normal monsters with ease, so I decided to up my exp rate and use the Wand of Polymorphism I had to morph small monsters into bigger ones. And all was well.
Until a monster morphed into an Ancient Multi-Hued Dragon, which in the game help files comes with a note: Beware! Well, I was confident that my mighty mage could deal with the dragon, so I started casting spells along the usual lines, but the problem was that the damn thing was resistant to most of them. However, it's attacks were not causing all that much damage, so I wasn't really in a big trouble yet. My Hobbit had 74 max hits, and the dragon did around 20 hits with it's attacks, so I had plenty of time to heal myself and get a couple of shots in. That is, until the dragon breathed fire. After which, my poor little hobbit had -622 hit points. Considering that the ultimate goal of Moria is to slay the Balrog, it's safe to assume the Balrog is more badass than the dragon, which lead me to the conclusion that Moria is a BADASS hard game to beat. Of course, I've never beaten it, but presumably some people have, and my hat's off to them.
