Interesting concept and cool aesthetic! The shadows and music make the game really creepy even though it's minimalist pixel graphics. Nice job on that.
It was not immediately apparent that the boxes were interactable, since they cast such harsh shadows I assumed they were solid pillars. There were also some actual pillars the same 1x1 size that looks visually identical, so I was running around trying to figure out what was a pillar as opposed to the box I needed to unlock the doors.
I got to level 2 and there was a visual glitch with the weight plate being rendered on the top layer (above the player and spider, but below the boxes), so I accidentally got stuck between the boxes and couldn't see my character, making me an easy prey for the spider with no where to run :( I thought I was gonna win that time cus I still had 3 hearts after I collected the boxes. Requiring the spiders as the final trigger for the doors was really dangerous with how fast they moved. If I had a way to freeze the spider in place temporarily, that would have been a much more fair fight!
Nice execution on the concept though! I enjoyed the game although I wasn't able to beat it. Great work on the fog of war effect!