This is really cute! The colors are amazing (makes me super excited for Fall and really sets the tone well) and the character design is great. One super minor criticism I'd have for the art is that it is sometimes difficult to tell the foreground from the background (for example, in the straight-on view of the main building, which otherwise looks amazing, it took me a second to realize that the things above the cabin were supposed to be trees in the background.) But considering this was all done by yourself in a month, I'm super impressed by how much quality art you got done. The fact that the characters have regular clothes PLUS costumes is so cute.
I really liked the story. I only found two of the three endings, but enjoyed the ones that I saw. (SPOILERS) For such a short experience, you did a really good job making the characters likeable (which made some of their gruesome ends all the worst in a good way!). The humor was also fun, I really liked "Mark is really dead though" in one of the bad endings, it caught me off guard.
I'm unfamiliar with Renpy, so IDK how important this is, but just FYI I kept getting some pop-up errors at the top of the screen saying "Warning: Write error: FS error" whenever choices come up (like whether or not you want to hear about the camp's history or where you want to go).
Overall, really happy to have played this! Happy Halloween!