I don't think it will be too effective unless you add more towers, like other people said. Since you have a hill, you could add more rings and towers (don't be shy on towers!) and you basically have Minas Tirith from The Lord of the Rings
However, I'd recommend a Bastion Fort, specially if enemies have gun powder
A bastion fort, star fort or trace italienne, is a fortification
in a style that evolved during the age of gunpowder when the cannon
came to dominate the battlefield. It was first seen in the mid-15th
century in Italy.
The design of the fort is normally a pentagon or hexagon with
bastions at the corners of the walls. These outcroppings are present
for the purpose of a total, panoramic view of the battlefield. Because
of the bastions, archers and cannon operators can hit any target on
the battlefield without having to lean over the wall and expose
which proved to be quite effective...
According to Geoffrey Parker in his article, The Military Revolution
1560–1660: A Myth?, the appearance of the trace italienne in early
modern Europe, and the difficulty of taking such fortifications,
resulted in a profound change in military strategy, most importantly,
Parker argued, an increase in army sizes necessary to attack these
forts. "Wars became a series of protracted sieges," Parker suggests,
and open-pitch battles became "irrelevant" in regions where the trace
italienne existed. Ultimately, Parker argues, "military geography", in
other words, the existence or absence of the trace italienne in a
given area, shaped military strategy in the early modern period.