I've killed Stone and his pet, and have made my way to Needleman's storage. But is there anything else to do in the fortress part? Those 3 locked doors at the top of the arena where you fight stone are aggravating me, and I'm afraid I've missed something somewhere...

I've also found that invoker jewel and overloaded the machine (what was the purpose of that??)
Also, how do you get the chest that's in the room you teleport to, near where Stone is? There's a dragon on the opposite wall that shots a one-hit-kills fireball as soon as I try to go for the goodies.
Many thanks for any help you could give
