Dorcasia, like Camelot, was a fairly well regulated place until the evil Zendos threw the main switch and plunged the country into perpetual darkness. The 'spirit' of each month of the year was trapped in a secret rune and then tucked away in the depths of his castle.
As might be expected you must search the castle and destroy the hour glasses which hold the months. There is also a runic inscription on each glass and you must decipher that to exorcise the spell on the month.
As there are 12 months there are 12 separate quests, all of which interlink to some extent. To solve the full puzzle you must break a number of codes and the game becomes more difficult as you progress.
Like its predecessor, The Oracle's Cave, the game features animated graphics. The explorer walks and climbs from location to location encountering various monsters and magical objects. Those are finely drawn in attractive colour and are an improvement on the Cave's rather monochromatic pictures.
Text can be used as in a standard adventure and the buffer will accept reasonably complex sentences, including some adverbs.
The Runes of Zendos is carefully produced and will have considerable appeal to amateur cryptologists.