11th Hour Cheats

At the monitor adjustment screen that displays a skull, type PP. Then, Right-click at the title screen to bypass the introductory sequence.

Get to a point in the game where you have access to
the altar room. On the side here, is a bowl you can click. There
is a page sticking out among the bones that says "Missed".
This is an obvious reference to Myst and pages, the game
that the 7th Guest was accused of trying to mimic.

To bypass the introduction sequence;
Type P, P at the monitor adjustment screen.
Then, right-click on the title screen as soon as it appears.

A the load screen (the one with the skull, type this case and space sensitive phrase: Roberto Dan R Zaphod B [Space]

After inputting the cheat, press the following to skip to a point in the game.
A - End of first disk
S - End of second disk
D - End of third disk
F - End of fourth disk
E - Go to the Olive In Stein riddle
G - Go to the Let's Make A Real Deal FMV