Because it hasn't been made...
This game is a shump game.Basicly a third person shooter.It is extremely popular because it is driven by the fandom with there being 10,000 fan arranges of songs,millions of images,hundreds of fan games and it has MANY characters.There are 19 official games in all 1,2,3,4,5,6,7,7.5,8,9,9.5,10,10.5,11,12,12.3,12.5,12.8,and 13.These games are all from Japan made by one man.Illustrations,music,progaming and story by Jun'ya Ota.He goes by ZUN though.Every game that isn't a .3,.5,.8 game play in the same style.you use the Z,X,C, and Shift for attacks and the arrow keys to move.Z is for the shooting,X is for bombing/spell card and the C is use in 13 to use a new feature.There are six stages in the games and an extra stage only unlocked after defeating all six stages in normal mode or higher.The exception being Touhou 7 which has a phantasm stage.9.5 is a game with a character called Aya Shameimaru who is a tengu reporter.You take pictures and you do not shoot.Same with Touhou 12.5.Touhou 7.5,10.5, and 12.3 are all fighter games(Oh yeah)They are 5 button fighters counting all the buttons except the graze,which is the super dodge.Supers are replaced by spell cards and the cost are other cards.You can only have 20 cards in all.12.8 takes place in the war between fairies.Since they are weak it is an extremely challenging game...
Note:The video only shows up to 10.For more info on each individual game.Go here:http://en.touhouwiki.net/wiki/Touhou_Wiki
This is one song Touhou is recognized by alot of people because of this...