Yes, there is a gap there, but when rendered out, you don't see the gap, it just looks like the top part is back a bit. DON'T move it if it bothers you(since that is not allowed), hide it with objects infront of it or lighting or add another block. Either way, everbody will have the same set up for those pieces so don't worry about it. :)

Also, the rules are not that bad. Just don't use any objects that are people or creatures/animals. I think we all know the difference between a blob that kinda has a shape like a person and a real poser figure with a stone texture on it to look like statues. :)