Legacy of the Wizard (1987), released in Japan as "ドラゴンスレイヤーIV Dragon Slayer IV: Drasle Family", is actually a part of Dragon Slayer series. This is a nonlinear platforming adventure game, in which you gain control over one member of the Drasle family to explore the vast dungeon filled with mind bending puzzles and obscure secrets.
The goal of the game is to retrieve a powerful sword named Dragon Slayer, protected by four magical crowns, to kill an evil dragon trapped in the nearby labyrinth. Each member of the family has different abilities, and the portion of the labyrinth only he/she can go into to retrieve one of the crowns. However, this prerequisite was circumvented by the clever use of certain glitches.
Lord Tom improves on his previous run by 58 seconds through more intense RNG manipulation in order to get the required items faster and better resource management. For more details, you can read the author's notes here.
This movie has a full Atlas Map encode, which shows the standard encode overlaid on a zoomed out map. The YouTube encode also includes the author's commentary in the form of subtitles.