I'm playing the original Metroid on an emulator. I don't want to have any advantages that I wouldn't have on a real NES, so I don't want to use savestates.

I have two energy tanks. After dying, I get my password, and inputting this returns me to the nearest elevator with all my items, including the E tanks... but they're empty. Since I'm about to go fight Kraid, cue fifteen minutes of farming enemies for HP. This promises to be super fun as I accumulate tanks.

Is there a legit way to load my game with my energy tanks full? Or are you actually intended to have to farm for health every time you load the game?

2 Answers 2


The password format has been thoroughly documented, and there are no bits used to specify Samus' actual health.

In other words, you have to farm health every time, or start using emulator features like save states or memory modification.

  • 2
    I would personally , after d ying multiple times in the same place, enter ur password, farm for energy tanks, go to where the password puts you, and save the state. its the SAME thing as energy farming, but not EVERYTIME. that's just tedious for no reason.
    – Ender
    Sep 2, 2013 at 16:37
  • @Ender Well, not no reason. It's tedious because changing the save/password system to encode health may have been prohibitive without cutting other data. Sep 2, 2013 at 20:35
  • @SevenSidedDie Surely they could have added an extra two characters to encode energy. I may indeed break my no savestates rule for this.
    – Jack M
    Sep 3, 2013 at 7:15
  • @JackM: Keep in mind that you don't normally see the password until you die. At that point, your health would be 0, so you'd have to reset the value anyway. Adding the current health would rarely provide much benefit, plus it'd make for an awkward password length (27 characters, since each character adds 6 bits of information and the health value uses 16 bits). Fixing it to 30 health keeps things simple. Sep 3, 2013 at 8:46
  • @Jack The password already encodes 128 bits. On hardware like the NES, adding 16 bits onto a value that already maxes out a register could easily have effectively added a full extra 128 bits. Sep 3, 2013 at 15:17

Since I'm about to go fight Kraid, cue fifteen minutes of farming enemies for HP.

There's an E-tank in the room you fight Kraid in so just get it when you enter the room. IIRC getting an E-tank refills your HP to 100% - even if you are at the max 6 tanks.

For a similar reason, save the one in Brinstar for right before you go fight Metroid.

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