Ahhh, you're completely right about the framerate limit.
I will admit the lack of clarity about sneaking is likely a failure on game design on my part (I'm much more of a programmer than a designer), as I struggled to find a way to cohesively and clearly show that the stealth is sound based without giving myself too much work in the time I had to do it. The creature has a hearing range dependent on if you are crouching, walking, or running, and will move towards any sounds it hears. I am unsure about the issue with the rocks...
Thank you for your feedback, it's a learning experience for me (my first jam!), and I still have a LOT to learn! Otherwise I hope it was at least a neat little experience. :)