Metroid II: Return of Samus
Metroid II: Return of Samus has been hacked.
M2Edit is a Metroid II editor that can edit the tile arrangements and the tiles themselves, as well as the maps of each room.
Metriod 2 DX is a hack of Metriod II: Return of Samus that makes the game use color palettes.
A debug menu exist in Metroid II: Return of Samus. It allows some game items to be obtained, via a very simplistic menu via pausing the game (with the debug menu flagged). This RAM cheat can access that menu. 0101A0D0