There's a reason for it being a million seller - it was priced at £19.99 upon release and it's been slashed to £12.97.
If you could pick up NMh, Z&W, Boom Blox or pro evo for just over £10.00 then hey'd be million sellers too. This is the price that Carnival games, Game Party and EA playground are all priced at and have been priced at.