Sorry for asking this here and not in the game's sub forum, but... well, it's sort of dead there, and I'd like to get an answer in this millenium :)

Basically- I'm heading into the Catacombs now, but Yorick keeps telling me to return to the Castle and gather artefacts, and while in the castle he keeps telling me to gather runes. The thing is, I think I gathered all I can, and explored every room, so I'd like to know if I'm missing anything. I'd really hate to have to backtrack through the entire game later on, but I'd also rather not spend hours searching the same rooms over and over for things that are not there.

I have four artefacts (according to the note I found)- the Root, the Horn, the Orb and the Bladed Sun, and five runes- the wave thingy, the triangle, the eye, the comet-ish one and the tree.

I don't want to look at any walkthroughs, as I don't want to spoil anything for myself, just to know if there is anything left to find in the areas I'm about to leave.