Cheat mode:

Note: This procedure involves editing a game file; create a backup copy of the file before proceeding. Use a text editor to edit the "options.ini" file in the game folder. Add the line:
set cheats=1
Then, press one of the following keys during game play :
Result - Key:

Shield - C
Advance to final Boss - X
Display information - I
Background - B
Weapons - [2-9]