I think you all nailed it with the details and as @ullreym say’s the camera angle.
For me the icing on the cake is the detailed colour (proper spelling), notice in the lower image from @dostovel the roof tiles, the variation in colour, also on the wall, the rocks etc. etc. whereas the other is blocks of colour, the leaves on the trees are one shade of green, the rocks are all the same base colour. The first image’s texturing highlights the low poly look, the second is a combination of low and high poly, the building is fairly low poly (I’m not entirely convinced it’s even classed as low poly, we would need to see the wireframe), but the trees with all the leaves are high poly. It actually works to serve the purpose of conveying high detail in the overall image.
The cherry on the cake is the artist’s passion for their art and vision when starting a piece, so two cherries on this cake.
I’m not much of a fan of @blanchsb ‘s example. The use of image textures in this example in particular looks to me like someone has cut images out of a magazine and made a collage. I know this is a style in itself but it’s not for me.
