This tech demo (not even a full game) is firstly controlled from an overhead view, meaning detailed textures/characters are not needed making the graphics easier to control/make look better. The demo doesn't even have characters to render and the enemies are a joke (little square bots). DD can be played from an first-person view allowing you to see the beautiful textures, background, characters/enemies, etc. Then you add in the all of the things happening on-screen (hundreds of enemies), and DD is far more impressive, at least imo.