Motion plus

The Wii MotionPlus

The Wii MotionPlus is a Wii Remote enchancing device that increases the sensitivity of the Wii Remote, so that MotionPlus compatible games feel more realistic. This device comes bundled with Wii Sports Resort and is required to play the game.

This accessory features an accelerometer that enables actions to be replicated identically in real-time.  

If you want to play two-player games in Wii Sports Resort, you need to buy more Wii MotionPlus accessories.