I love the concept a lot! The lack of instructions, as well, makes it feel more... introspective, I guess, as the player is left to find things on their own.
However, I think that various indicators would help improve the experience. I see that people have already mentioned a map and a points counter (that would be especially helpful given that when I first saw the graves, I thought I'd need to destroy one to get the artifact). I think a clock indicator (probably something that has a sun that rises and sets, to keep the immersion) would be a good way to tell how long you have left before you have to set up camp again. I actually spent more than a day trying to find somewhere to bury the artifact, so I don't know whether that time limit is really implemented in game or not.
More fleshing out the world would also be pretty cool - insides of buildings, various decorations or items that hint at the lore, etc. - though I think the minimalism of art style definitely sets a tone for the game that I wouldn't want to change.