While holding L and R press up, up, down, down, left, right, left, right, X, O All weapons and weapon upgrades
While Holding L and R, Press Triangle,Triangle,X,X,Square,Circle,Square,Circle,Down,Right Ammo Refilled
While Holding L and R, press Up,Up,Down,Down,Left,Left,Right,Right,Square,Triangle Invincibility
While Holding L and R, Press Triangle, Triangle, X, X, Square, Circle, Square, Circle, Right, Down Unlimited ammo

Avoid Lava Damage  -  In the Dead Guppy & The Seep Levels, when you fall in the lava, you will take a lot of damage so. Use the "Scythe Hop" continuously to reach a stone to grab yourself with Square.

Ledge Grabs & Combos  -  In the room with Smith and Weston, go up to the door that you exit through. You can perform an unlimited amount of ledge grabs. If you shoot one of the computers in the room before you begin the ledge grabs you can perform an unlimited combo.

Scythe Combo Moves  -  After you collect four Weapon Widgets, pay Smith & Weston to unlock "More Scythe Moves" Then, use the following combinations:

Circle Spin:  Press Square(2), Triangle.

Uppercut:  Press Square(2), X.

Dive Attack:  Press x, Square

Powerful Combo Hit:  Press Square(3).