I like it... The only thing I think you did wrong was spend to much money on materials. It prob could've been done cheaper with less materials..but hey if you ever wanna turn it in to a deck just push the kennals off. The only other prob I just thought about which prob wouldn't happen but could would be a accidental fire.
Threw this thing together today. Still got to run a water line to it and come up with some kind of presidential solution to run the dog turds back to a ditch behind it. There's a few little things I keep thinking of to change but its coming along.