They're backed up by an even better song list than the first game's, one which casts its net a little wider while still ensuring everything is recognisable and danceable. Most importantly, it acknowledges that the disco doesn't discriminate on cool – so you'll find Justice, Digitalism and the Ting Tings sitting next to It's Raining Men, The Monster Mash and Boney M's Rasputin (complete with Cossack dancing). There's a huge spread of styles and eras too, from the electro bump'n'grind of Ke$ha's TiK ToK to Harry Belafonte's vintage calypso. Turns out that waving your arms around, laughing like a drain and looking like an idiot are great equalisers in taste.
The only disappointment is the increased number of session-musician covers. Some are more convincing than others: Madonna's Holiday is uncanny, but there's a distressingly insipid run at Crazy in Love here. At least we get to hear some classic recordings too, like Quincy Jones' Soul Bossa Nova and Ike and Tina Turner's Proud Mary. The latter brings the house down every time: the most energetic numbers, such as this, Hey Ya, Rockafeller Skank and the incredible endurance test that is Snap!'s The Power, are the ones you find yourself returning to time and again.
A few numbers a day is a reasonable little workout, actually, a fact recognised by the new Just Sweat mode that awards you "sweat points" for your efforts and assigns mild, tough or intense daily programs. It's hardly Wii Fit or EA Sports Active, but it's arguably a more enjoyable way to work up a sweat in your living room.
It's also one of the very few excuses you'll have to fire up Just Dance 2 on your own. The fact is that, although the routines are fun to learn, there's nowhere near enough precision in the motion-detection or interest in the simple scoring system to reward solo play, and with everything (very sensibly) unlocked from the start, there's no incentive to solider on either.
Just Dance is, you see, something of a con. With the game only detecting the motion of your right hand holding the Wii remote – and even then, it seems to be much more sensitive to force and timing than actual direction – you can play it like an orchestral conductor from the sofa. It's so imprecise that you'll struggle to improve your timing in an effort to get reliably better score ratings, and since you can't ever fail to finish a song, there's no inherent challenge. But if you're playing it with that mindset, you're doing it wrong.
Because despite all this, the better you dance – and the more you move your whole body, learn the routine and enjoy yourself – the better you score. Just Dance's mechanics may not be a science, but they might just be witchcraft. Judged by the developers' own criteria for success – getting players to lose their inhibitions, feel the music and, well, just dance – it's a roaring success.
Just Dance 2's final additions are a much-needed download store for songs – thinly stocked, currently, but it works seamlessly – and a couple of multiplayer modes. These improve on the first game's but are, frankly, surplus to requirements. The game is playable by up to four at absolutely all times, and adding spurious competitive mechanics just breaks up the routines.
In the end, those routines and the tunes they're crafted around are the only things that matter. The game system and the technology, slender and unreliable as they are, are irrelevant. In a way, that might be the best thing about it.
Just Dance 2 is impossible to play with a furious frown of concentration on your face, and just as impossible to play without a wide grin. It doesn't reduce music and dancing to precision beatmatching or button-pressing: it's about surrendering to the free-spirited, glorious silliness of it. As Junior Senior sing: everybody, move your feet and feel united!
Well, your right arms, anyway.