Animaniacs

In Level 2, after the stage with the chandeliers, jump over the fire and you will get to a part where there are two stones and two boxes. Smash the stones with Wakko and pull back one box with Yakko. Now, make sure that the second box is where you it was when you smashed it. If you walk all the way to the right and then back, the other box will disappear! It doesn't hurt the gameplay since you can still do whatever the game asks for with one box.

To get the box back, just walk all the way left and back.

Enter these on the password screen for the desired effect. Grid order from Left-to-Right, top-to-bottom.The password grid will turn blank again if they're entered correctly (with exception to the Level Skip cheat).After entering any of these, either choose "BACK" to go back to the title screen and start the game normally, or enter a proper level password.

Note: The "Limited Invincibility" cheat will make you invincible to most hazards except for spikes, bonfires, Pinky & Brain's "vacuum tuba" device in Stage 3, and "Instant Kill" situations.

At the password screen, enter these in order from left to right, the going to the next line all the way to the left:

To save your score, lose all your lives and say no to the continue screen. After that, you will be given a password in which you can continue your game with however many stages you cleared and the score you had.

To unlock Stage 4, beat stages 1-3. After the credits, do to the password screen and there will be a password. Press Start to get Stage 4.