Thank you for the feedback. I'm a bit new to this, is it okay if ask what are some specific ways I can add post processing/effects that I could add? I didn't use an engine to make this and just used HTML and Javascript. I'm glad to hear you enjoyed it!
Me too, I did my game without an engine and adding camerashake and postprocessing might be a bit complicated. My suggestion would be (it isn't real postprocessing but improves the graphics) to add some kind of shadows in the UI for example, or to make the screen darker on the edges to make it feel more creepy.
Overall still a great game, nice that you made that with HTML and JavaScript! Well done