The following info comes from the Switch stage show that Nintendo put on in Japan.

- development is pretty much finished

- the producer wanted people to get hands-on, but since the release is farther off, Nintendo decided to hold back

- the theme of the game is active exploration by players

- the objective is to rescue princess Peach

- Mario goes out from Mushroom Kingdom and travels a “certain Earth” with a hat-shaped airship

- go on adventures across various countries

- many ideas were gathered from the team to implement in the game and they build each one into a playable form

- the team keeps playing those elements over and over again

- the team only throws these ideas into the sandbox if they find it to be really fun

- Mario will have more facial expressions this time

- the hat is still a secret

- in desert buildings, you can enter and explore inside

- in the desert, go and explore a tower and Tokyo Big site-esque building which you can see far away

- the forest is well-suited for exploration

- the devs are putting effort into showing nice-looking grass and sunlight through trees

- in the city, Mario can jump to the ground from the top of a skyscraper

- you can also jump on/step on humans