Sometimes, you may play a game, and even if you don't expect it to be easy, it's sill a lot harder than you thought it would be. I don't mean if you're unfamiliar with it, like the first game you've played of a particular genre. Nor do I mean the game is hard because it's broken (bad controls, collision, camera).
I can think of two games that surprised me with their difficulty.
The first Legend of Zelda game was a lot harder than I expected. I never played it until shortly after Link's Awakening came out, and I had beaten that game, Link's Adventure, and Link to the Past. None of those games were cake walks, but this was something else. It took me weeks just to beat the first quest.
The Pocky & Rocky games surprised me. They aren't as hard as Konami's other shooting series (Contra, Gradius, Parodius), but these games still handed my ass to me a few times. It was my first taste of the "Cute 'em Up" genre, and I knew never to expect a free ride from a cute facade.
So did you every find a game you found harder than you thought it would be?