I like to shoot night shots like this with water too. I am guessing that you had to use whatever was handy for a "tripod" with the result being the out of level horizon. Did you use the low ISO to get the longer exposure, or was that an oversight? Nice shot for just a snapshot while out and about, without actually being prepared for it.
LOL, we all want to crop your fun picture. I'd just as soon see the foreground shrubbery go and leave just the water, lights and sky. Makes it something of an abstract. So now you have opinions all over the place. Which means, Ithink, that you did a good job.
Like the blue light on the right, too bad it does not reflect. Agree with suggestion to straighten horizon and crop sky. If this is a high resolution image, could even do drastic cropping, keeping just the lower right quadrant.