Unlockable List
Complete the game under the normal difficulty setting to unlock Hard Mode.
Complete the game to unlock all levels under the difficulty setting used.
Complete every level under the hard difficulty setting for unlimited shield.
Complete the game under the normal difficulty setting and get an "A" rank on each level for unlimited ammunition.
Complete the game under the hard difficulty setting with at least a "B" rank on each level for unlimited grenades.
Complete the game under the hard difficulty setting with at least a "C" rank on each level for unlimited health
Complete the game under the hard difficulty setting with an "A" rank on each level for a selectable left-weapon.
