When Super Mario 3D World hit the Wii U, 4 players could enjoy much of the adventure together, but not all of it. The Captain Toad levels that were included could only be played by one player. That's set to change for Super Mario 3D World + Bowser's Fury.
According to the official website for Super Mario 3D World + Bowser's Fury, the Captain Toad stages will now allow support for 4 players simultaneously. That might make puzzle-solving a bit more hectic, but it's still great to have these levels opened up for multiplayer.