In Hosedown you have to defend yourself by shooting Miis that throw mud and run towards you and mud creatures that are stronger and also run towards you. The Mii you're playing as can shoot them with water, where you aim by moving the gamepad around and shoot by placing your foot on the balance board. The harder you press down on the balance board, the more powerful the shot of water is. If you run out of water, you have to wait for it to fill out again. The Mii has three hearts and if you get hit three times, you will lose.
The difficulty levels are set in different areas, going from Wuhu Town to Summerstone Castle and finally the Mysterious Ruins.