From the announcement:
After having been on hold for a while at the US customs, our shipment of Twin Tin Bots to the US eventually cleared customs and is on its way to US retailers as we speak !
Philippe Keyaert's new game was only available to a happy few KS backers in the US, and will now hit the shelves, thanks to our distributor Iello USA.
This first batch is limited in quantity (about 850 copies), so get them while they're hot! :-)