There does not seem to be much to prototype. You answer some few questions and a mysterious narrator railroads you into behaving how they tell you. Could make for an interesting horror about obedience but there's very little to comment about
Downwards does not position itself as a full-fledged project. This is an ordinary prototype / technology demonstration, which is mostly needed for the developer. For the most part, this is an interactive diary of early sketches and concepts that will be revealed only with the release of a full-fledged game, which is currently actively under development.