I think the details are great! The tablecloth, the chairs, the railing, the couches, the stairs going to the middle level and back the other way to the upper level in shadow. The shadows left by the two different lights. Nice.

I think you could work on the proportions. From my limited knowledge of construction and archictecture I would imagine the level with the dining table on it was an add-on. A more realistic solution to the space problem - i assume here that the floor and ceiling can't be adjusted but the table level can - would be to raise it about 2feet. The first stairs would come out further but there's a little room to play with. The dining table would then be higher and the level of the windowsills would be closer to a realistic height from the table - so that people sitting at the table could enjoy the view. If the distances are arbitrary I would just adjust the proportions so that the couches had some head room - otherwize anyone entering the little couch alcove would dent their forehead on the beam.
Nice work!