First, your horizon is very very very close to being level, but at this size, it's dropping a few pixels to the right. Line up the left side with the top of your browser window and you can see this. Before you get to the pier, you can see a few pixels of open sky. That's #1.
#2 - I think the composition is ok. I think I probably would have used a longer lens and stepped back a bit to make the pier larger and more prominent in the shot. As it is, it's quite small and doesn't contribute as much as I would like. I like the framing, but I don't like the focal length.
#3 - It appears a bit too yellow but I can live with it.