The techinque of using 3d prerenders as 2d sprites in games is not new, and most of the time, these are easily distinguishable by their specific 3d-look. E.g.: Pulstar, Mars Matrix.
But I've been always wondering how Cave (Progear, ESP Rade, Guwange...) does it.
The graphics in these games of their, while certainly being prerendered (or so I heard?..), just look so pixel art.