Pokémon RBGY/Unknown Dungeon

Cerulean Cave (ハナダのどうくつ aka "Hanada no Dōkutsu", meaning "Hanada Cave"), also known as Unknown Dungeon (ななしのどうくつ aka "Nanashi no Dōkutsu", meaning "Nameless Cave") during Generation I, was changed for every Japanese release. The Japanese Red and Green had a layout that was changed for the Japanese Blue, and this revision was retained for the international releases of Red and Blue. Yellow had a layout only used for that version, albeit a simpler one. FireRed and LeafGreen appropriately went full circle, using the original Red and Green layout, updated and with Rock Smash-able rocks added to it.

All comparisons below use the Japanese versions as reference.

==Floor 1F==

Notice how the layouts of the cave in the Japanese Red, Green, and Blue are actual mazes: the player will get to dead-ends and has to find the right ladder to proceed. In Yellow, on the other hand, the path was made more linear and straightforward. Also, note how the layout in FireRed and LeafGreen is a mere graphical update of the original Japanese Red and Green layout.

==Floor 2F==

The most uneventful floor, yet the most tricky to navigate. Basically, the ladders remained in the same position and the maze changed between the revisions.

==Floor B1F==

The bottom floor, where item placement also changed, but the layouts generally have a straightforward path to the main reward in all the revisions: Mewtwo.