Boulder Dash Construction Kit

Boulder Dash Construction Kit is both a full game and a level editor, built around the gameplay mechanics of the original Boulder Dash (1984). You still play as Rockford, the pixelated, googly-eyed spelunker, digging through caves, dodging falling boulders, and collecting diamonds before time runs out. But the real star here is the Construction Kit; it let players create their own levels, a rare and powerful feature in the mid-80s.