As Capcom tells it in the video below, Dark Void Zero was originally created for Nintendo's ill-fated PlayChoice-10 cabinet but never released. It has supposedly (nudge nudge, wink wink) been resurrected from "the vault" for download on Nintendo DSi.
Dark Void Zero features a human named Rusty fighting a group called The Witchers, with the help of scientist Nikola Tesla. Rusty is equipped with a rocket pack that allows him to fly around levels at will. Dark Void composer Bear McCreary has been hired to craft an NES-style soundtrack for the title.
Dark Void Zero is scheduled to be released some time in January for 500 DSi Points.