So my two cents is for the castle. It isn't just a square flat building like the 1st pic. But if you would like to improve it a little add some more texture to the walls so they don't look so flat/same. Also, try to build with the terrain a bit or at least sculpt the terrain. The Blood Magic alter looks like a sore thumb because the the way the terrain was cut out to make room for it. If you want to level terrain for something like that fine. But at least sculpt the terrain a bit afterwards to bring more a natural look to it again and remove that abrupt edge.