The niches on the sides of the second floor look bizarre without a wall on their north face.
Also,
Basically, this illustrates your 'aversion to symmetry' that Mr. Burns mentioned (that you seemed to somehow not read). The ellipse at the bottom, there is more space on the right than there is on the left. This is once again illustrated with the two lines directly above it. The two ovals about center of the image mark the plants that they encompass, showing that they are at different heights on the map.
The two lines at the top show that the right side of the map is about 1 tile wider than the left. The more circular outline shows where a niche
should be, but isn't. The rest of the lines show things that should be aligned, but aren't.
Also, your shadow placement makes it seem like the light is coming only from the left, when really it's coming from pretty much everywhere. I also think the door on the lower right needs some re-evaluating, it would seem much better if its handle were on the other side.
Keep in mind that most of this is nitpicking, but it really makes your game look better.