In the SNES version of Mario is Missing, a map of whatever city Luigi is in can be displayed by pressing Select. However, the map is actually present at all times during gameplay, even when the screen is showing Luigi walking around the city, by being drawn on the SNES’s third background layer.
The first background layer depicts the sidewalk Luigi walks on as well as the buildings next to it, while the second layer depicts the rest of the city further back. By toggling the second layer off, it reveals the map on the third background layer, which even has all the animated map sprites loaded on it during gameplay when they would never be seen, instead of displaying them only when the map is brought up.
As such, there are actually always two Luigis present in every gameplay scene: the controllable Luigi in the foreground and another Luigi hidden in the background on the map screen (see the top left corner of the map in the footage). While this is clearly implemented simply to save time when loading the map (by having it always remain loaded), it is a highly unusual way to do so.
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