Castlevania: The Dracula X Chronicles would be the only game on a newer system I had problems with, the funny thing is, it's a remake of an old Castelvania, besides that I can't say I had problems beating games on newer systems, or maybe I just haven't stumbled upon hard ones yet. But the games from NES/SNES era were giving me a serious headache, games such as Contra III: the Alien Wars, Gargoyle's Quest, Battletoads, and many more.

There were also a few games on my old 486 I never managed to beat, the only games I can remember right now is Titus Fox and Dangerous Dave.