User summary:
The Wizard's Citadel was the second adventure in a planned series of eight linked adventures (only the first two actually were released). The adventure was announced for the BBC Micro, Spectrum 48K, Electron, and Commodore 64 - though only the BBC Micro version actually was released.
The compact cassette included, on Side A, a character generator that allowed for the creation of a D&D-like character, complete with equipment and spells, or for the import of a character used in the first adventure.
Side B then presented the adventure. After completing the adventure, the character could be re-loaded into the generator to gain experience, rest, and recuperate - and also be saved for the (presumed) next adventure in the series.
In The Wizard's Citadel adventure, the character gets caught trying to steal from a powerful wizard. Instead of eliminating the character, the wizard sends them on a quest to gather items.