The castle was rectangular in design, across, and would have comprised four corner towers, three side towers and a large gatehouse, all protected by a water-filled moat; the centre of the castle would have formed a courtyard. Of these buildings, only the gatehouse and the west tower survive today, partially intact. They are constructed with decorative brickwork and stone detailing, in a fashionable late 15th-century style, and have various symbols built into their walls using darker bricks. Twelve gunports for early gunpowder artillery were built into the walls of these two buildings, although historians are uncertain whether these defences were intended to be practical or symbolic. The government body Historic England considers the castle to be a "spectacular example of a late medieval quadrangular castle of the highest status".