Interactive Fiction have posted an interesting article on EMI's puzzles. They talk about the evolution of puzzles, where some of EMI's puzzles went wrong, and why the rest were good.
There is more to Escape from Monkey Island than gratuitous references to earlier games in the series or the sight of Guybrush Threepwood in a pirate bathing suit; namely, hard puzzles that are reminiscent of an earlier age in adventure games.To read the article, head on over to Interactive Fiction
Source: ZeroXcape