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