Variant Space Octet was written by the original scenario writers (Naotaka Hayashi and Toru Yasumoto). It introduces the concept of "World Line Fluctuations" in a way that Zero would later expand upon. Many fan theories about Zero 's ending are tacitly confirmed in the hidden routes of Octet .
Make sure to check the system requirements and platform availability before downloading the game. steins gate variant space octet download