1. So i went into the cellar with my warlock and his pet imp, the first thing that imp did, was destroying the ladder to get upstairs. While moving around that imp destroyed a few more crates
2. in the last room there are 2 unreachable greatswords
3. hidden room
so either the acces to the hidden room seems buggy or its a deathtrap feature. when you trigger the 2 chairs (tried it with characters and vases both same result) to open the wall, the wall moves up and down randomly. you can still jump through to access it, though.
