Level skip -
While playing a game, press [Ctrl] + [Alt] + [Shift] + [End]. Note: You will 
not collect money from the current mission.

Blooper mission -
Note: This procedure involves editing a game file; create a backup copy of the 
file before proceeding. Use a text editor to edit the "user.cfg" file in the 
game directory. Add the following lines to the file, then start the game and 
begin a new mission:

play 
starting_mission 16

Alternately, install Dromed from the Goodies folder on Thief Gold disc one. 
Then, start Dromed and open mission 18. Press [Alt] + G after it loads to enter 
the game.