I hear that amazon.co.uk pre-orders for the game & watch: super mario bros. went up and were sold out in 20 minutes. nothing yet for us here in the states yet.
they're also up on amazon.co.jp, but no shipping options to the u.s.
https://www.amazon.co.jp/dp/B08HJ9T6GY/ref=sr_1_2?dchild=1&keywords=game+watch+mario&qid=1599569026&sr=8-2