Values Dissonance: Quite possibly why the game is far more successful in Japan than everywhere else. Japanese gaming culture is more communal and more open to players sharing strategies at arcades, which was vital if players wanted to complete the original game, especially before the age of publically-available, fast, and affordable internet coupled with sites like StrategyWiki and GameFAQs. In the West, the concept of arcades as social environments is generally lost on players, so players weren't as willing to collaborate to figure out how to find the next treaure. This is made worse today with the idea that using guides and asking other players for help makes you an idiot who shouldn't be playing the game.
That said, Namco Museum Volume 3 includes a hint booklet providing a general walkthrough, and Namco Museum DS can also display a hint guide for the current floor on the screen opposite of the screen being played on.