There's a bug/glitch in the first scenario of the Burgundian campaign so that you may win the mission and get the "No wheels" achievement within five minutes.

When you attack the Liege villagers outside (north and south) of the city, they will not garrison into the TCs and simply walk around to be slaughtered. So that means you can simply send your initial troops to north and south of the city and kill the villagers until the number is below 15, and you will win and get the achievement pretty easily.