After completing the game, it's revealed that Samus made a small engraving on the base of the Ruins Test boss when she had lived on the planet as a child. The image is of herself, Old Bird, and an unknown Chozo that may represent Gray Voice.

Crocomire was originally going to be in the game, but was cut for unknown reasons. Crocomire can still be accessed by hacking into the game's code, but the existing animations are seemingly unfinished and there's no death sequence.