The game in question is none other than Diddy Kong Racing, the 1997 hit from Rare that remains the only true kart-racing rival to Mario ... Nintendo 64 (later re-released on the Nintendo DS ...

TL;DR: Nintendo announced the Switch 2 with Mario Kart 9 as its first game, potentially supporting up to 24 players, doubling the previous limit. The trailer shows wider tracks and smaller karts ...