Try out these handy passwords to unlock goodies in the game. Normally you'll be given a password if you lose - but if you need one quickly and don't want to torture Samus into getting one:
Use the following code to reach the end of the game:
This password drops you off in Tourian will all items secured.
Use the following classic code for a neat surprise:
You'll start off in Norfair with both Ridley and Kraid history and have in your possession 255 missiles, five energy tanks, the Varia Suit, Wave Beam, Hi-Jump Boots and Screw Attack. Samus will also be sporting an armourless purple undersuit appearance, something you normally don't see unless conquering the game in under three hours.
This sneaky password will give you some unusual effects:
(The "O" in SWORD is the letter "O", all others are zeros)
You'll start in Brinstar with everything you need to take on Ridley and Kraid (both are still around). The strange part is, you'll have no missile indicator but can fire as many as you want. Picking up health and taking hits has a weird effect as well, as sometimes taking a hit actually gives you more energy, while picking up an energy ball sometimes drains your health.