About
Metroid is Nintendo's 1986 action-adventure game, first released for the Famicom Disk System and later for the NES. Metroid for MMC3 is a disassembly of the NES Metroid, reworked to use the MMC3 memory controller instead of the original MMC1. The source is better organized and commented and leaves out much unused code and data. The author describes it as a foundation for Metroid modifications or total conversions.
How it differs from the original
Because of the memory-controller change and removed unused code, the assembled ROM is not identical to the original, but it plays the same, apart from running a few cycles faster in limited cases while frame timing stays identical.
Getting started
Run the included build script for your platform to assemble the ROM with the bundled Ophis assembler; a separate script builds the original MMC1 disassembly. Building on Linux or other Unix systems requires Wine.
History
It is based on Kent Hansen's original Metroid disassembly, which Nick Mikstas further organized and commented.