Complex sentence: First released in Japan in April 1999, it was later released as the first "Stadium" title in Western regions the following year, and is a sequel to the Japanese-only 1998 Nintendo 64 release, "Pokémon Stadium".
Split into simpler sentences: First released in Japan in April 1999, it was later released worldwide the following year. Released as the first "Stadium" title in Western regions, the game is a sequel to the Japanese-only 1998 Nintendo 64 release, "Pokémon Stadium".