One of the core tenets of Nintendo is to bring people together over gaming, whether it be local co-op, online co-op, LAN play, or even asymmetrical multiplayer. This mantra carries through even in games that most people would expect to only be single-player titles. In fact, it was recently revealed that Super Mario Odyssey will actually feature co-op play.
During one of the Treehouse live-streams, Polygon took note that a demonstration featuring game director Kenta Motokura took a decidedly different turn while the developers were showing off gameplay for Super Mario Odyssey. Motokura detached the right Joy-Con from the base and handed it over to one of the other Treehouse members, and she was able to take control of Cappy, Mario's magical hat companion in Super Mario Odyssey.
In the two-player local cooperative mode we learn that one player controls Mario and the camera with the analog stick, and can jump using the bottom face button when the Joy-Con is turned side-ways. Instead of having access to the camera with the second analog stick, the top face button must be used in combination with the analog stick to control the camera.
The second player, however, can take flight using Cappy. We see that the second player can freely fly around as Cappy and collect items for Mario within the view of the screen. The Cappy player also has very limited control of the camera, being able to look around just a bit on their own.
Polygon also notes that the player in charge of Cappy will be invincible, so they don't have to worry about dying when playing as Mario's magical clothing accessory.
Some of you might have some flashbacks to playing as the star in Super Mario Galaxy, which had an almost identical two-player local co-op mode. One player would control Mario and the other player would control the star, helping Mario by attacking enemies or collecting items.
This also reminds me of the co-op modes in the old 16-bit Sonic The Hedgehog games for the Sega Genesis, since it was similar to how a second player could take control of Tails in Sonic 2 and Sonic 3. Tails was invincible for the most part and could really help Sonic out during some tough situations.
In the case of Super Mario Odyssey for the Nintendo Switch, we find out that not only can Cappy fly around, but it's also possible to help Mario solve some puzzles in the game, too.
During the live-stream presentation we get to see that one of the tasks of Mario is to collect the Moon runes throughout the game worlds. In order to get one of the runes he has to complete a puzzle involving collecting music notes scattered around the treetops. For a single player it could be pretty difficult, but with the help of a second player controlling Cappy, it becomes a lot easier to complete the challenge.
The feedback for this feature has been nothing but positive, and many people have praised Nintendo thoroughly for adding in a local co-op mode for Super Mario Odyssey, which is due out this holiday season exclusively for the Nintendo Switch.