Castlevania too tough for you? Then don't try to play Batman: The Video Game. When ol' Saint Peter stops me at the pearly gates and asks me, "Have you paid your dues, Larry?", I can look him straight in the eye and say, "Yes sir, I beat Batman: The Video Game."
Okay, I did have little help in the way of the Nes Advantage for that last Joker fight. Besides Batman for the NES there is only one other game, the arcade version of Marvel Superheroes, that has made me think I might have a small heart condition. After defeating both of them I found I had shortness of breath and my vision has become...odd. Though nothing that a giant slurpee couldn't solve either way.
Though only five levels in length it felt like a whole lot more aided by the number of villains in the game. Heatwave, Deadshot, KGBeast, Javelin, Maxie Zeus, Shakedown, Killer Moth, The Electrocutioner, Firebug, and of course the Joker. Plus about a hundred robotic cameras and lasers, etc.
I've thought about taking this one off the shelf again and giving it a try...but then my chest starts to constrict slightly and I play a round of Duck Hunt instead.