Die Hard 2

During play, type "KAREN" for invincibility.  
A flashing cheat icon will appear in the upper left corner 
to let you know it worked.  
Now use the following keys:

F1              Jump to part one of the current level.
F2              Jump to part two of the current level.
F3              Jump to part three of the current level.
1-5             Jump to the corresponding level.
U               Flip screen upside down and back.
R               Restart current level and collect bonus.
W               Select weapon.
D               Program information.
G               Add grenades.
M               Add gun clips.
.               Add to life meter.
ENTER (keypad)  Kill all enemies on the screen.