There are a few secrets inside the game. Probably the one that is the most difficult to find (as the player tends to skip the credits) is an extra scene involving the remains of the Monkey Combat between LeChuck and Guybrush.
There are other secrets hidden in the game, such as when you go to the Palace of Prostheses check for the name Ryan J. Danzwithwolves before looking for the no-nosed man. After you get the name check on the option menu and you have Murray the Skull pinball, (or as it appears in the game Murrayball), also there is another mini-game.
When you complete the Monkey Combat chart, you can play a game based on space invaders, Monkey Invaders; is really cool as the Monkeys take the role of the space invaders.
Beside these secrets and the only cheat, there aren't any more things to explore in Monkey Island making the experience a little restricted on terms of cheating the game. But cheating is not an option on Monkey Island as the game is really simple and enjoyable. But if you are planning to acquire this game, the only option that will have is in the PS2, as original copies of the PC version are scarce and as sharewares there aren't many places to download the full game online. If you have the game, treasure it, is one amazing jewels of the video game history.