It has been a loooong time discussed theme on this planet, but if you think about that deeply…the game has many secrets that can be taken as the main secret
Possible ways to signify the secrets:
The Monkey Island itself! It has never been tracked or written into the maps! Does it exist?
To travel to the Monkey Island is a mystery! but some people made it! How?
The legends talk about the Ghost of the pirate LeChuck! is he real? or rumors?
The Monkey Island has a big Monkey head! Why?
The Monkey head is a big maze! how will you pass through?
How Cannibals know how to make a root beer! and How do they know it kills the ghosts?
The Cannibals have a dead head! a zombie head that can talk? and navigate?
Herman’s friend is hanging on the tree and Herman calls it accident! is it true?
so, now we have 8 secrets that can be the game main secret