The Lord of The Rings: The Two Towers::

Slowmotion:
First beat the game using any of the three characters and the hidden level with Isildur. Then while playing, pause and hold L1 + L2 + R1 + R2 then press Triangle, Circle, X, Square.

Infinite arrows/axes:
First beat the game using any of the three characters and the hidden level with Isildur. Then while playing, pause and hold L1 + L2 + R1 + R2 then press Square, Circle, X, Triangle.

All upgrades:
First beat the game using any of the three characters and the hidden level with Isildur. Then while playing, pause and hold L1 + L2 + R1 + R2 then press Triangle, Circle, Triangle, Circle.

Invincibility:
First beat the game using any of the three characters and the hidden level with Isildur. Then while playing, pause and hold L1 + L2 + R1 + R2 then press Triangle, Square, X, Circle.

Always devestating:
First beat the game using any of the three characters and the hidden level with Isildur. Then while playing, pause and hold L1 + L2 + R1 + R2 then press Square, Square, Circle, Circle.

Tiny enemies:
First beat the game using any of the three characters and the hidden level with Isildur. Then while playing, pause and hold L1 + L2 + R1 + R2 then press Triangle, Triangle, X, X.

Restore health:
While playing, pause and hold L1 + L2 + R1 + R2 then press Triangle, Down, X, Up.

Restore Ammunition:
While playing, pause and hold L1 + L2 + R1 + R2 then press X, Down, Triangle, Up.

Add 1000 experience points:
While playing, pause and hold L1 + L2 + R1 + R2 then press X, Down, Down, Down.

Level 2 skills:
While playing, pause and hold L1 + L2 + R1 + R2 then press Circle, Right, Circle, Right.

Level 4 skills:
While playing, pause and hold L1 + L2 + R1 + R2 then press Triangle, Up, Triangle, Up.

Level 6 skills:
While playing, pause and hold L1 + L2 + R1 + R2 then press Square, Left, Square, Left.

Level 8 skills:
While playing, pause and hold L1 + L2 + R1 + R2 then press X, X, Down, Down.