Log Message:
Add games/taisei.

Taisei (lit. Occident) is a free and open-source fangame of the Touhou
series.

Basically, it is a shoot 'em up game with lots of bullets (the genre is
literally called bullet hell). It doesn't aim to rebuild a particular
installment of the Touhou games, but is rather an original game set in the
world of Touhou.