The hex grid (rather than, say, square, or random Voronoi regions). The fact that some hexes have 1 voter and some have zero (rather than, say, all hexes having 1 voter, or any having more than 1). The circular colored dot indicating the voter's party (rather than, say, a picture of a horse, or tinting the entire hex). The "Hint", "Reset", and "Submit"/"Call election" buttons below the grid, in that specific order; and (I assume) the nature of the hints. The "health bar" graphic depicting the number of horse voters and donkey voters.
Also the unrealistic mechanic where a tied vote removes that district from the total.
Now that I find a more compelling argument than "Hey you used hexes". It might still turn out to be a similar "obvious" choice but unlike the hexes it's not the first idea that comes to mind.