Anyway, this was based off of Irisu Syndrome, and from the simple editing of the hiragana as well as the context I'm gonna go out on a limb and guess that the flash game is called "Erosu" Syndrome. Irisu plays a little differently, though, since you use both mouse buttons and shots stay on the screen.
You get more options in free mode depending on how many points you score, and if you had let the headspawn things reach her breasts to get the bad ending. You want 1,800,000+ points to complete one set of unlockables and 1,000,000+ points as well as getting the ending to complete the other set of unlockables.