Alright Raptori... this was actually one of my favorite stories. I only have a few comments. The prose is excellent as is the writing in general. My only concern was the pacing.
You start strong, the first few lines caught my interest well. I like how it begins with "The stars are a lie," like he knew it from the first and then forgot in his pain. Very cool. For me though, the "finding out where I am" part, took a bit too long. I don't know which part could be removed, or if it is even necessary, but I lost some interest during this section. I'd say there are two options here: either tighten it by removing some of the exposition, or interspersing his exploration of the cave with his memories of how he'd gotten there. Personally I think the second option is the better.
The human sacrifice part was cool, I didn't see it coming, but I feel like the reveal would have been stronger if you had set up the memory in a way that we see his journey to the tribe and his time among them so that the sacrifice comes as more of a surprise.
Your concern about the ending is partly unfounded, I think. I love that he has to gamble by leaping into the river, but I think what is missing is a sense of urgency. He doesn't fully explore the cave, which doesn't quite make sense on its own. If he had an injury that created a time constraint so that he must take this gamble now, or if he had fully explored the cave and decided this was his only option, I think it would work better. As it is now, it seems like he is just assuming there isn't another way out. I feel that if you made the cave smaller, made him feel trapped and desperate, it would add some tension and really make me believe that diving into the river is his one and only hope.
Hope that helps. Overall a great story, you two(?) have done well.
