Did you know that Mario vs. Donkey Kong was going to use the Mini Marios trapped inside crystal balls as keys originally?
Probably not, but a few old beta pictures show this...
Anyways, I've found a way to give the crystal ball with the Mini Mario inside it's beta behavior back!
It is pretty much identical to how the key behaves in the final game normally!
You can pick it up, carry it around and throw it.
In order to finish a level in the beta you had to carry the crystal ball to the door.
In the final game the key replaced the crystal ball idea and the sprite for it was used for a new level type where you just have to break the ball in order to finish the level.
Sidenote:
The ball turns into a generic key when Mario unlocks the door, because the old animation used in the beta does no longer exist in the final game...
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