Nate has been gracious enough to host a wiki containing all of the information we've gathered on formats used throughout their games, please feel free to post any questions you have here.
@Mods I posted this thread here "Gaming" as it's not Metroid specific, if you feel it's more suited somewhere else, please feel free to move it.
EDIT:
Here is the link to the wiki: Retro Modding Wiki
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