Based on the Isle of Gelnor, Phantasie allows a group of six characters to adventure the countryside and try to defeat the evil Black Knights and their sorcerer leader, Nikademus.

By selecting "Random" one could also choose from ogre, troll, pixie, gnoll, orc, lizard man, minotaur, and other races.

The game was notable for taking advantage of a broad mix of styles for the game: a town window which allowed purchasing in various shops, a top-down style dungeon crawl view, a top-down world map, and a separate combat window.

[2] Game reviewers Hartley and Pattie Lesser in 1987 complimented the Atari ST version of Phantasie in their "The Role of Computers" column in Dragon #120 (1987), recommending that Atari ST owners should "consider Phantasie as a game well-worth their attention".

[3] ANALOG Computing in 1988 called Phantasie and its sequel the best fantasy role-playing games for the Atari 8-bit.