It could be the smaller sizes presented here, but in the first two photos the rocks in the foreground don't appear to be in real sharp focus. I think the images would be better if they were (again, assuming they're not).
I like the tones and moody feel to the third one, that's an interesting one! It could well be the cloud formations giving this impression, but this one kind of looks like the horizon is a bit tilted. I like this shot.
The last one is quite striking, lots happening in that scene! Again though, it could be the size here but the foreground doesn't appear to be in real sharp focus. Otherwise, like I said, I find this to be a striking scene.