Also, I love surrealism.
And yet, I get much more of a sense of bad perspective than it looking surreal. You wondered if there were any major violations in perspective, and as Jad mentioned the bricks would be it. My advice would be to redo that entire side and make all the lines in between each brick at a straight vertical instead of the ~60 degree angle. If you insist on the lighter face of the brickwork to remain as it is, there could be some ways of embracing unrealistic perspective views to make it seem intentional. Maybe skew the edge of the tower to be at some angle that doesn't match up with either face (as well as the rear profile edge of the tower)
There are plenty of other perspective issues everywhere. If you'd like a visual post pointing them out to get to know perspective drawing better let me know I could draw guidelines to help you out.
As for the clouds... I'm not much of an expert on those. My advice though would be to follow what you have going on in the top middle chunk of cloud. It's profile edge where cloud meets sky isn't using the super dark values (unlike the chunk to the left of it) the edge is chaotic and wispy instead of smoothed out (unlike the chunk to the left AND right of it)
Any other cloudy stuff that I might recommend is more easily communicated through an edit...but I don't have time for that at the moment :X