Just like the old NES games. You've captured the feel and atmosphere of the 8-bit age perfectly. Incredibly hard, but perserverance will always get you though like any good game - no "fake" difficulty, just poor reactions on the players part.
For all the people slagging this game off, I suggest you take a long, hard look at yourself in the mirror, then give yourselves a lobotomy. Dont downvote a game just because you lack the skillz or patience to beat it.