Completion bonuses:
Successfully complete the game under the easy difficulty
setting to unlock the special menu and movie mode.
Successfully complete the game under the normal difficulty setting
to unlock two player mode. In this mode, one person moves using
a Dual Shock 2 controller, while the other shoots with a GunCon2.
Successfully complete the game under the normal difficulty setting
with a rank "B" or greater without using any Resurrection
Packs to unlock infinity mode. Complete the game on Normal without using a resurection pack and
get at least an overall B grade at the end of the game.
Successfully complete the game under the hard difficulty setting
to unlock the game art.

Shoot credits:
You can use your gun to shoot the ending credits.