Love the game btw, but this bug is really rough. I think the bug has something to do with the shining gem, maybe the backpack, and stairs but I'm not 100 percent sure. Basically the shining gem began duplicating while on stairs (as well as other items, in my case it was health potions) and dropping from my inventory while the game yelled at me that I was overburdened. This locks the player character up, and duplicates items. I got rid of the gem and that stopped the duplication, but after a few steps the player is locked and unable to move, even when under carry capacity. 2 questions are: what files do you need to look at to find the bug and is there a way to save my playthrough? The second is not as big of a deal of course.

Edit: Turns out I also have the Leprosy thing going on like Failnaught, so that explains the movement thing, but the item replication was really quite strange.

I've been hearing of quite a few issues with the code checking your inventory size. I'll take a look. I think your best bet until I get a fix out would be to save and quit once you are again under capacity (maybe give it a little extra room) then try to stay under the limit. I'll do my best to get the next version out as soon as I can, but I'm still working through the bugs backlog on top of a quest overhaul. 

No worries, thanks for the reply!