Level Select
At the main screen - hold down SHIFT and enter this code using the arrow keys:
DOWN, RIGHT, LEFT, RIGHT, LEFT, RIGHT, LEFT, UP
Abe will say "OK" and you will be given a listing of all levels. Select which one you want to play and press ENTER to begin.
Note: Starting a level in this way is not particularly good if you want to get the "happy ending" as the game assumes that all the mudokans from the previous levels were killed (ie: Starting level 2 in this way means that you start off with NO escapees and 28 casualties.)

Movie Select
At the main screen - hold down SHIFT and enter this code using the arrow keys:
UP, LEFT, RIGHT, LEFT, RIGHT, LEFT, RIGHT, DOWN
Abe will say "OK" and you will be given a list off all the game's cut scenes. Highlight the one you want to view and press ENTER.