Hard mode:
Successfully complete the game under the normal difficulty setting to unlock
the hard difficulty setting.
Level select:
Successfully complete the game to unlock all levels under the same difficulty
setting initially used.
Unlimited shield:
Successfully complete each level (including the training level) under the hard
difficulty setting.
Unlimited ammunition:
Successfully complete the game under the normal difficulty setting with an "A"
rank on each level (including the training level).
Unlimited grenades:
Successfully complete the game under the hard difficulty setting with at least
a "B" rank on each level (including the training level).
Unlimited health:
Successfully complete the game under the hard difficulty setting with at least
a "C" rank on each level (including the training level).
Selectable left-weapon:
Successfully complete the game under the hard difficulty setting with an "A"
rank on each level (including the training level).
Sites: