3D Ant Attack (1983)

The player controls either a boy or a girl (the game allows the player to choose at the start) who has to enter the walled city of Antescher (a reference to the artist M. C. Escher) in order to rescue their significant other who has been captured and tied up somewhere in the city. The author argued that it "was the first true isometric 3D game". (wikipedia)
Genre: Action
Platforms: ZX Spectrum, Commodore 64
AKA: Ant Attack
Developer: Sandy White
Publisher: Quicksilva