[2] The game involves the construction of a series of castles in Wales and the Welsh Marches during the 13th century.

[2] The game combines several genres of gameplay including resource management, a text-based multiple-choice storyline and a simple combat mode.

Each scenario starts in the castle building mode with a flat, empty map of the region.

On this map the player designs the outline of a castle, including a gatehouse, walls, and round or square towers.

Wall defenses feature cauldrons of boiling oil and towers include arrow slits.

In order to finish the stage, one complete circuit of stone walls and towers, including a gate, must be fully constructed.

During the winter months (December through February) construction stops, and workers simply consume the food supplies.

During this playing phase, the player is presented with the view of the king's throne room, as he is visited by a messenger or a leader from one of the factions.

The decision made can influence any part of the game, including the royal treasury, diplomatic relations with the various factions, or even incite immediate combat.

Combat is fast-flowing, and the only user intervention during this time is to instruct individual units to attack specific enemy targets.

If any single enemy troop manages to reach a wall segment, they will begin to tear it down.

At the start of the game, the player is asked how many castles they wish to construct (3, 5 or 8), thus dictating the length of the entire campaign.

Castles are constructed one after another, and each scenario is more difficult than the last, in terms of available resources and money, the size and variety of enemy troops, as well as the difficulty in maintaining good relations with all the different factions (friendly or otherwise).

Originally developed for DOS, Castles used CGA/EGA/VGA graphics and supporting AdLib MIDI sound, as well as a mouse interface.

The program employs a simple point and click interface, supported by pull-down menus.

"[5] The game was reviewed in 1991 in Dragon #175 by Hartley, Patricia, and Kirk Lesser in "The Role of Computers" column.