Unlimited plasma:
Enter L.F.C as a name at the start of the game.
More Gold Plasma:
If you need more Gold Plasma to upgrade your ghost in the ghoul room, go onto the high score board. Keep playing the same missions repeatedly until you have enough Gold Plasm to upgrade your ghost to its full potential.
Game ends before it starts:
If at the name entry screen you answer their question (Is there anyone there?) with a negative answer (for example, “No”), the game ends.