Interesting game, I liked it. At first I thought that the darkness/insanity mechanic might be a bit too fast... but then I realized that all I needed is a lamp and stop worrying. Pressing it once every 1-2 seconds makes the game quite a bit easier :D. Might need to reduce the battery count in the DLC Areas by 1.
Really did enjoy how you have to hide from the spider. It hindered my way of progression at times. The Mystery box was just as I imagined :3.
Though what I've noticed is that in my playthrough is that by hiding away from the Spider, it's head becomes loose from its appendages (once it deaggros) and teleports downwards, which caused this bug in the picture at some point.
It never moved again afterwards.