The horizon is off a little bit. I think it was half a degree according to photoshop. I downloaded the photo, measured the horizon. Rotated the canvas to it then to the horizon. Trimmed the photo to get rid of the white edges. I can barely see the difference and I measure angles for a living. The way I originally noticed, after the comment, that it was unlevel was by using the scroll bar on the right to line up with the left side of the horizon and saw a little tiny sliver of water on the right.
I was just amazed that the other guy could tell that just glancing at it.