First, your illustrations are great, I love the style you used, really think you captured the essence of your story/narrative.
I think you also did a great job with the sanity and health system, maybe it could be cool to see some more text styles or transitions depending on how low the health/sanity levels are. You used them a few times towards the end, but I noticed that you can lose quite a bit of sanity before even seeing the sludge monster. Could be interesting to try out!
Really awesome work! :)