Hunter: The Reckoning

All Weapons
Press Up, Down, X, Y, Y.
(Thanks to schad@hotmail.com)

Alternate Ending Sequence
Save over 50 Innocents before returning to the train.
(Thanks to schad54321@hotmail.com)

Unlock Nightmare and Ultimate Hunter Modes
Finish the game once, then look at the Special features screen.
(Thanks to schad54321@hotmail.com)