It's a good way to translate the experience of exploring narrow caves into a video game format. However, moving the mouse to move forward is a bit difficult. You have to use your whole hand. Plus, it might be better to keep the camera steady at this point, otherwise it keeps looking up and down.
I liked the atmosphere and the attention to detail in the notes and graffiti.
I found a bug. At the very beginning, when you enter a tunnel, if you move the mouse back to exit, you can't reenter the tunnel.