I got the Excalibur II twice. Once was just getting it, and the other was getting it while getting all the other stuff as well (doing a perfect file as mentioned above). It's just a built in challenge, it's kind of fun. If you go through the game this quickly then the Excalibur II will be uber powerful because you'll be at such low levels, but otherwise it doesn't really hold it's own as a weapon. A lot of people have done this, and there are guides with people doing this in a mere 9.5 hours. On my first file, I did it in 11 hours, and on the "perfect file" one I had like 2 minutes left. I don't see how it was done in 9.5 hours, but I guess it's possible.