I managed to somehow fluke my keychamber open relatively early on, but since then I'm no where nearer the "Extra Challenge" of opening up the whole thing
I know that whatever batteries that were in there when it first shipped have long since died a death.
I just use the Ramisis as a paperweight these days.
From what I gather, even when you do know how it all works it's still not very easy to open.
I liked the Isis opening method as it was tricky but quick if you knew what you were doing