Very 90s, like a console mascot version of Metal Gear Solid. Could be expanded to have enemy variants, different colored cubes. Also powerups, like temporary speed boost, temporary invisibility, or like a doppelganger/distraction. Maybe have some levels that are more hill-based to take advantage of the rolling aspect of the character, and have some hole hazards for him to drop into. Also, this is probably too goofy, but maybe a golf course or a putt-putt course level or mini game.