I actually don't consider that many game on the Neo to be crap, but if you're going by the general consensus than it would have to be Ashita no Joe/Legend of Success Joe. I find the overly complex controls intriguing. I mean there was four action buttons and they only used two, why? Instead of using the additional two buttons for different punches they instead decided to use every directional plus A or B to make a slew of punches. Then there's the AI, which by all accounts is brutal in the later levels. I do like how the game switches up from street fights to the boxing ring, adds a bit to the otherwise clunky gameplay. For a game being based on an anime it's about what you could expect, Dragonball Z being a prime example of botched franchise games.
