Personally I don't mind that games are getting easier. If you think about it, video games were one of the only forms of entertainment that you couldn't finish. When you go to the movies, you expect to see the whole thing, and if you couldn't, you might demand your money back. That's how I feel about games, especially because I tend to play for the story more than anything else. So it is nice to be able to finish any game that I buy. Having said that, there have been a few games that I really couldn't get through. F-Zero GX (I think that's what it was called) on the gamecube. That was one of the least forgiving racing games I've ever played (just above star wars racer), which is a shame because it was a lot of fun. I never did finish it. Also Ninja Gaiden cut me off after the third or fourth level. I don't remember what was happening in the story, but it just kept sending wave after wave of guys at me and I never could push through it. I will also mention The Legend of Zelda: Oracle of Ages. While it wasn't necessarily unforgiving, the puzzles in that game melted my brain. I beat it once and never looked back.
Also, on a side note, if you're looking for a modern day game that is challenging, I hear that Dark Souls will kick anyone's butt.