To go to a secret bonus level, enter BCDF or GYLM.
To access a different secret level, listen up. Type in the code to go to level 9
(WBGR) and play through the next 4 levels without letting any of the victims die. As soon as you rescue all of the victims in level 12, you'll automatically go to a bonus level as soon as you walk through the exit door. Also, you don't have to enter the level 9 password, instead you can play all the way through it, but in the long run, it helps.
Added by: biehlza Oct 23rd 2009, ID#142