What a nice entry, full of charm.
The gameplay loop is a bit opaque at first but that's on me : I did not read your tutorial. After understanding that I had to hold Z for the grave to get dug everything wen't smoothly. Very nice gameplay loop, having to remove each teeth individually while the skeletons grew closer is a super nice touch.
I won't repeat too much what others have already said but tools are mostly not worth the price they're sold at. I've used my initial stash but never felt the need to buy more. I think the holy water would be a lot better (and more valuable) if it was thrown a bit further. As it is, it's basically a worse version of the shovel.
Still, extremely solid entry, I had a really pleasant time.