kioh_gyoku
Kioh Gyoku (稀翁玉, lit. "Rare Venerable Orb") is a vertical-scrolling danmaku shoot 'em up, and is the second official game in the Seihou_Project by "Shunsatsu sare do?" (at time part of Amusement Makers). It was released specifically for the Windows operating system around December time in 2001. It is a unique game where two players indirectly battle one another by charging and releasing charge attacks and bombs upon the other player, similar in the style of Phantasmagoria of Dim.Dream.
https://en.touhouwiki.net/wiki/Kioh_Gyoku