Wizardry I・II contains the first two installments of the Wizardry series: Proving Grounds of the Mad Overlord and Knight of Diamond. Both games were ported to the PC Engine (TurboGrafx) CD console with various enhancements, unreleased separately. In fact, the two games are merged into one, as the player is able to play through both of them continuously directly from the main menu.

Though the game(s) are rather faithful in gameplay and graphical design to the original computer versions, the enhancements are significant enough to consider this release a remake. Similarly to the NES / Famicom version, the dungeons have simple graphics, unlike the computer originals with their vector lines. Enemy sprites are also more detailed and occupy a larger portion of the screen.

A pre-made party of six is available to the player right at the beginning, consisting of characters with generic names ("Fighter", "Samurai", etc.); creating own characters (unlike in the modified PC Engine CD version of Might and Magic), however, remains possible. Dungeon navigation is accompanied by orchestrated CD audio music in this version. The battle music is in PSG format.