Metroid is the first game in the Metroid series, released for the FDS is Japan and then ported to NES. All information in this section will refer to the ROM “Metroid (U) [!].nes”, file size 131,088 bytes, for information related to patching this ROM please check Patching a ROM for more information. (there could probably be a lot more put up here)

For editing Metroid you have a choice of two editors currently, Editroid and MetEdit, the former being actively worked on, these two tools should cover most of the hacking done to Metroid, however a few additional tools exist, such as Metroid Tuner, a list can be found below.

• Editroid (available on the Tools page) - Wanna hack Metroid? You need Editroid! Can't lose that belly fat? You need Editroid! Are you drowning in credit card bills? You need Editroid! Do you want to please your lover in bed? You need Editroid! That's right! Editroid is the tool to fix any problem that can be fixed by editing Metroid!
• Metroid Tuner - Sweetass Metroid music maker, crank them tunes out baby!

• ASM patches/hacks - Code to make changes to the game engine
• Complete Dissassembly - The entire game dissassembled and commented here, feel free to improve it

• Editroid - Reference guide for Editroid, useful for a quick look at its features and functions, as well as any shortcuts that might exist.
• Metroid Tuner - Quick reference guide to Metroid Tuner, the music tool for Metroid.

• FAQ - Frequently answered questions here, if you got a problem, this might have the answer!
• Editroid Crash Course - For your first time with Editroid
• Data Structures - Detailed information on how the game world is built and how Editroid works with it.
• Doors in Metroid - Connect rooms without breaking things

• Pointers in Metroid - How pointer values relate to ROM locations
• Metroid Tuner Guide - From basic operation to the finer points on dumping and inserting songs.

• Projects - Details on using the built-in assembler to do nifty things that Editroid doesn't support out of the box

• ROM map and RAM map available on DataCrystal (these are rather incomplete)
• Complete Disassembly. Based on and extends the Original Disassembly.