Here are some cheats and tips for the game Hellfire.
Expert mode:
Enter the options menu and select the “Hard” difficulty
level. Wait on this screen until the difficulty selection changes
to “Yeah, Right”. Game play will begin with increased
difficulty and 99 continues. Note: An alternate method of enabling
this mode is to enter the options screen and set the sound test
option to “8”. Expert mode will begin when the music
ends.