10-2/IceTop: A duplicate of Icicle Mountain, sans music. Meant as a placeholder for a second Ice Climber stage, which never made the cut.
TEST: An enormous stage, possibly created to test Adventure Mode mechanics (I can’t imagine why else it’s so huge). It’s background is a grainy photograph of a Cafe in California. Why this photograph was used as a backdrop is beyond all human comprehension. DUMMY: Consisting of an invisible platform, over a black background, with no music, DUMMY is the nightmarish, existential hellscape where Sakurai hides his contempt for his fans.. and Ridley. He’s there too.
AKANEIA: Swedish for “reclining chair”, Akaneia is a non-functional stage - in the sense that it’s currently impossible to access by any known means of hacking. Sakurai confirmed that it was intended to act as home for Marth/Roy
Both 10-2 and AKANEIA laid the groundwork for the Ice Climber and Fire Emblem stages in Brawl.