Aaaargh. Mouse dexterity testing is incredibly irritating when you're using a TrackPoint (rubber nipple mouse) :P

On a slightly more serious note, this is awful for anyone who has mouse dexterity issues, like older or inexperienced computer users, those using assistive devices, or even people with shaky hands. It also relies in some places on culturally specific assumptions (for instance: put toppings on a pizza... I see some squiggly reddish stuff which seems like it's meant to be bacon, but in the UK bacon doesn't look anything like that!)

Good on them for trying to make the CAPTCHA experience more interesting, but this isn't quite a complete solution...