Hidden Level:

Triangle, X, Trianle, X, Circle, Square, Triangle, Circle, X.

Infinite Ammo:

X, Triangle, X, Square, Circle, Triangle, Square, Triangle.

Infinite Lives:

Circle, Circle, Triangle, Circle, X, Square, Square, X.

God Mode:

Triangle, X, Circle, Circle, X, Square, Square, X.

All Guns:

Circle, Square, Circle, X, X, Triangle, Triangle, Square.

Hints

All Weapons:

Beat the game.

Bonus Level:

Beat the game with at least a 50%.

Unlimited Ammunition:

Beat the game with at least a 55%.

Unlimited Lives:

Finish the game with at least a 60% completion.

Unlimited Health:

Finish the game with at least a 65% completion.

All Cheats:

Finish the game with a 78% completion.

Mummy Returns Trailer:

Beat the game and the Mummy Returns trailer will be unlocked.

Thanks to Revolution readers Unknown, tony and The Temple Of Bastet!