what is that thing in the middle of the bridge?
That's an open bridge - most armored warships have two bridges, one in an armored citadel and an open bridge, sometimes completely exposed to the weather and almost always with at least an open top or very light structure (as the case is here) since the armored citadel was usually considered too restrictive to be a useful command center during normal operations and especially when leading fleet operations. This is why a number of things happened - why flagships started getting separate command levels, why admirals would be in the open bridge even during fleet actions and why they stopped putting in armored bridges alltogether (of course with postwar armor schemes it become a moot point regardless). It also looks like the armor bridge has been rebuilt too, a common practice with between-wars ships to try to make them more hospitable.
That said there's a lot about this ship that doesn't make sense, especially after most of the year spent drawing fine ships. You could get away with the bridge features stolen from a cruise liner but the black structures off to the side don't make sense and at this point and age even with a complete rebuild I feel it better justified to build a dedicated missile escort separately.