Ninja Gaiden - Unlockable Classics, Difficulty Worries?

Thanks to IGN Xbox for their hands-on look at Tecmo's Ninja Gaiden for the Xbox, as the eagerly-awaited ninja action title got an updated showing at the Tokyo Game Show. As well as what GameSpy call the "beautiful and frenetic action" of the main game, the developers showed off the NES Ninja Gaiden games that were recently announced as unlockable features, found "...hidden inside of a random chest. After finding it, series creator Tomonobu Itagaki directed us to a rundown arcade cabinet in the corner of the [in-game] room. Suddenly... we were playing the original Ninja Gaiden in all its 8-bit glory." Intriguingly, Itagaki was concerned that the new Ninja Gaiden was too easy, and "...said many Japanese gamers don't really like challenging games, and that he wanted to make sure the American fans were pleased and found the game challenging enough."