I returned to Prismatic Gate (before L12), Venser was there, I won and I got his cane anyway... 
... Well then. I think all of us beta testers owe Evan an apology for this massive oversight. You're not supposed to be able to do that. But hey, congrats on finding a bug and getting your cane. Let me tell you, without the gold tunic, he's MUCH harder
What exactly is the base damage of the Cane? I'm guessing it's between 8 and 12, but haven't been able to really test it. Even if it does a lot of damage, it uses magic up too fast for me to like using it outside of bosses.
It does double the damage of the final sword. As for magic use, rather than hold it out all the time, constantly turning it on and off can clear out enemies just as effectively while being much more magic efficient.
I found a way to F2 already, but I am in need of a key and I have no hookshot. :C
Also, I asked the exact same question yesterday, here: http://www.purezc.ne...=21#entry886524
If I remember right, you can go to the left side of floor 1. There's a puzzle with angel statues and blocks that rise up to block your path (or maybe doors that close, can't remember exactly which). If you go to the right side of floor 1, there's a room with angel statues and a path way on the floor that shows you where you need to walk in the other room to get through.