A classic for a reason. Ditched Machine X (a profoundly bad level) showed me just how little you truly need to set up a theme, as long as you have a little peritext to back it up. With just the title alone, Ditched Machine makes it feel like you are actually exploring the innards of a giant, nonfunctional machine, an experience that is also aided by the very electronic song. The gameplay almost veers into memory, but doesn't quite make it, which leads to the player developing an almost unforgettable knack for the level, formed from both a combination of visual cues and muscle memory. In the end, isn't that what most dual parts are about?