This is amazing. I'm curious, did you start with a photograph to work with for the land and the beach? Looks rather realistic. I find that would have a whole lot of effect if you incorporated the monster scene into an actual place somewhere. Would hit home and personal that way, if you're trying to knock some feelings.
This looks very surreal and realistic. The monsters are very much creepy and the scale is captured well. It looks a little artificial, however, how there are basically three monsters lined up. I think if you included some more silhouettes in the background, they would look more in place with each other. I love it none the less.