#1....perhaps u can straighten the horizon alittle....359 degree tilt...it will straighten the tower on the left half and give more visual impact...
#2 there's a bit of some building u left there..perhaps u can crop it off???
#3.....simply LOVE this pic....love the way u use the fisheye...,love the way u place the parapet(i presume) in the bottom right corner...gives a nice sense of depth.... leads me into the picture...
#4.....great...good use of fisheye and nice cropping....
overall: great...colours and composition work for me....