It looks good...but there are some problems.
For a start, i'd make it a nighttime scene with maybe a kind of yellow faint moon out of the window with a *very* slight volume fog.
The stairs need some tweaking...most of all because they don't appear to go anywhere and the lips look a little...funny.
That dry rock texture you have doesn't quite work...it looks a little flat. Try something else or make the walls geometrically (slow but it'll look good!)
The lighting needs some tweaking....even in daytime (unless there's no roof) the light will come from a definate location.
The coat of arms and the table look pretty good though.