Quake 4

While playing the game, press Back to display the objectives window,
then quickly press:

Down, Up, Down(2), Up, Right, Left, Right, Y, X(2), A  - Invincibility
B, A, X, Y, Left, Right, Left                          - Full ammo reload
B, A, B, A, Up(2), Down, X                             - Full health
Up(2), Down(2), Left, Right, Left, Right, B, A         - Get all

 