>>38660435To me, this is why Gen IV feels like a planned ending. They had Diamond and Pearl planned as early as Gen II, and Platinum and HGSS would arise naturally with third versions and remakes. Gen III feels almost like a stopgap where they didn't have the time to make full complete games like in Gen I and II. With Gen IV, you can see they brought back a lot of design philosophies from Gen II, like numerous baby Pokémon, cross-Gen evolutions, the day and night cycle, days of the week and timed events, honey trees, online functionality from Japanese Crystal, and even in-game events for Mythical Pokémon which traditionally didn't appear in the first games of a Generation. There are elements in the Spaceworld demo for GS that seem to have been cut until they were finally implemented in Gen IV as well. Then there were all the references to Gen II like the Red Gyarados TV report at the beginning of the game, the floor of Pokémon Centers having a gold and silver Poké Ball, the return of a "Park Ball" now colored gold and silver with a light blue middle, Jasmine appearing in the game, etc. And then when Platinum came out, they went as far to include a Battle Frontier and Gym Leader rematches like in Emerald and made Barry the first Trainer to surpass Gen II Red in levels.
Looking at the Spaceworld demo location names, the areas that would become regions were Kanto (corresponding to East), North (Hokkaido, which would become Sinnoh), South (Kyushu, which would become Hoenn), and West (Kansai, which would become Johto).