I'm in Jakarta, still wondering what Melty Blood: Act Cadenza could be (what can I say? Jakarta's a dull town). So I consult Wikipedia, which lays it all out for me. According to Wikipedia, Melty Blood is "a popular doujin game for the PC, created by TYPE-MOON and French-Bread, acting as a side story to TYPE-MOON's visual novel game Tsukihime taking place a year after the events in the 'happy' alternative ending to Arcueid's path."

So there you have it -- crystal clear. Now if I could just find an explanation for the giant spermatozoa...