Enable Secret Characters
To enable Burn, Keith, and Wong (from original Psychic Force), access Windows Registry (REGEDIT.EXE) and go to this address :
HKEY_CURRENT_USER/Software/TAITO/PF2012/SpFlags
Next set the value of 'Burn', 'Keith', and 'Wong' to 1.
WARNING: Always make a backup before editing your system registry.