If possible, add bushes and stuff. I haven't been mapping enough to know wether or not that is possible but I think it is.
Also, this might just be me; but I think mg_slender_wolf sounds quite ridiculous. Makes you think it is some kind of werewolf-slender mix-map. lmao
Just name it mg_slender_man/men depending on how you're going to make it, or something similar. There are multiple other ways to show the players that the map was made by S.T.A.R.S WoLF.
Oh, one more thing; I think it looks way too bright. In the real Slender game, you can't see anything but the sky and the top of the trees unless you are using a flashlight.