As title.... this is in-store only. Guy at the till said it was this price since it was the offer of the week. Not sure how long their offer of the week lasts, but if you're passing by any stores then it may be worth a look.
Haven't played it yet, but heard that although the visuals are amazing the actual game play is okay. So don't expect to be wowed... but at 20 quid you can't complain.