As you'd likely expect, Just Dance 2015 is a game that's really easy to pick up and play. All you need to do is hold onto your Wii Remote/Move Controller in your right hand (or rely on the Kinect/PS4 cameras to pick you up instead), and copy the moves of the dancer on screen. The closer you match your moves to the diagrams, the more points you'll score - but as there's no penalties for failing, simply having fun flailing about to music is perfectly acceptable too. With a mix of songs both old and new, over-the-top, daft dance routines and support for up to four players to shimmy along at once, it's the sort of game that anyone and everyone can play.
With accessibility in mind, Just Dance 2015 is made for multiplayer fun, with many of the routines designed to cater for several players at once (although they're all perfectly playable on your own), with each player often having slightly different, complimentary choreographies. A strictly competitive affair, the aim of the game is simply to out-dance your family and friends to get the highest score. Wii/Wii U players might want to bear in mind that you need to put a bit of welly behind your moves for it to pick it up correctly, while Kinect can have trouble following the movements of both groups, and smaller folks sometimes - especially if you end up overlapping each other due to not having a big enough living room. Younger ones may also find the move diagrams scroll by a touch to fast, or are a bit difficult to decipher (at least to begin with), but seeing as they can't fail, they'll probably be having too much fun to notice, that is.