Echoing other reviewers here: Very simple premise that was very spooky (been done before, but your execution worked!)
Potentially increasing player movement & look speed would help with the frustration folk were feeling trying to navigate the maze to find 5 objects? I know one of the Metro games had a similar enemy in a library. Rows of shelves broke line of sight pretty well and created suspense and terror because you didn't know how quickly they were coming for you or if they'd be around the next row.
You could also decrease the range that the enemy pursues you at and have more in the map, so you don't have to walk backwards the whole time but still get the "could be around any corner" effect.
Or maybe just keep one and teleport it ahead of the character at a certain point?
Great work for two days though! I've got a low threshold for horror, so I noped out after 2 keys, haha