Remember Gauntlet for the Nintendo? This is just like it but before Gaunntlets time. Run through a ton of mazes killing monsters to reach the end to kill the demon.

This relatively unknown top-down dungeon romp was one of the first RPGs that include a full-fledged dungeon editor program that allows you to design dungeons easily with a mouse-based interface (as shown in the screenshot). The game itself is less appealing, as it's a typical dungeon RPG where you control a party of 4 characters in search of treasures. Still, it's a solid cross between Gauntlet and Bard's Tale that allows 2 players to play together.