In-game pause screen hold Left Trigger and press quickly LB, LB, RB then hold Right Trigger and press quickly RB, RB, LB. To get back to the normal damage amount, do the same combo while the damage level was increased.

In-game pause screen hold Left Trigger and press quickly X, Y, Y, X, then hold Right Trigger and press quickly Y, X, X,Y. To deactivate God Mode, do the same combo while God Mode is active.

At the main menu hold both Triggers and press quickly X, LB, RB, Y, Y, RB, LB, X

Complete certain tasks to get each achievment:

Complete the following tasks to get game score points.