Slender: This has succeeded with an erie atmosphere. If this is just a concept without future development, well done, no need to read the rest of this paragraph

But I hope to see more. Now... the moon is out, there should be enough light to see outdoors without the flashlight rather than everything being totally black. At best I was able to get three of the pages before the batteries went dead. I think I located 5 of the pages overall after 4 game plays, unless placement is randomized. Bigger pages would be a bit less difficult and easier to read. Sometimes a page was snatched up before I got close enough to read it. The map should be a smaller area with everything pushed closer together, or let the player walk faster. I held down 'W' the entire time. The 'taken' effect was cool.
Despite criticism, Slender has potential to be a spooky mystery without the need for monsters to pop-up around every corner. Barista 2, the concept game based on Quake 2, would be a good reference.