What do Mega Man 9, WipEout HD, Ninja Gaiden, and Devil May Cry 3 all have in common. If you guessed that unforgiving difficulty was the commonality, you are right. Indeed, we've seen the gradual reintroduction of games with difficulty levels so taxing that it brings back memories of some truly daunting games from the 8-bit and 16-bit eras.
Mega Man 9 and WipEout HD are more recent examples, but it can be argued that Ninja Gaiden and Devil May Cry 3 are two games that really put the hurt on unsuspecting players.
Games Are Evil analyzes the difficulty curve and asks "Do games really need to be frustratingly hard to be good?"