The third installment of the work-in-progress shows the center portion with the two towers on both sides. They are built on raised platforms and have snipers locations overlooking the level area.
The far side has been built with the sloped entrenchments that have to be breached in order to reach the next level. There are a couple of surprises on the grid that can only be seen if you look closely enough. ;)
Last but not the least, the flag tower and other structures are remaining to be built.