Lol first of all the girl is really Kawaii XD... i think when you made this walllpaper.. you pictured her walking over the beam... lol to tell you the truth i got the impression that the beam is rather high XD... to me you should have added a little something at the bottom of the wallpaper to keep some sense to it XD...maybe adding grass or woodwork...
But as to the wallpaper artistically i find it great for your first scenic attempt XDthe light source fix quite nicely and the clouds loos great ;)
Great job!
