I'm the one who added it, maybe I didn' explain it very well. It's not just a change of graphic options (as in, a simple video resolution change). The game contains two compressed files, each of which contains distinct textures and models (which are the "low-res assets" and the "high-res assets"). IMHO, the notable part is how only the pixel shader 3.0-compatible video card can use the high resolution textures and more detailed model; conversely, the less performing video cards cannot use the high-res assets (=it's impossible) and the high-res assets file can even be deleted without any repercussion on the game.